更新

.gitignore

@@ -0,0 +1,25 @@
+# 排除可执行文件
+*.out
+*.o
+
+# 排除IDE配置文件
+.idea/
+.vs/
+.vscode/
+
+# 排除Trae AI配置文件
+.trae/
+
+# 排除编译输出目录
+output/
+
+# 排除临时文件
+*.tmp
+*.temp
+
+# 排除系统文件
+.DS_Store
+Thumbs.db
+
+# 排除竞赛平台配置文件
+.cph/

exercise/src/Main.java

@@ -0,0 +1,59 @@
+import java.util.Scanner;
+
+public class Main {
+    static boolean isPrime(int x) {
+        if (x < 2)
+            return false;
+        if (x % 2 == 0)
+            return x == 2;
+        for (int i = 3; i * i <= x; i += 2) {
+            if (x % i == 0)
+                return false;
+        }
+        return true;
+    }
+
+    static boolean noZero(String s) {
+        for (int i = 0; i < s.length(); i++)
+            if (s.charAt(i) == '0')
+                return false;
+        return true;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String s = in.next().trim();
+        boolean left = false, right = false;
+        if (noZero(s)) {
+            boolean ok = true;
+            for (int i = 0; i < s.length(); i++) {
+                int v = Integer.parseInt(s.substring(i));
+                if (!isPrime(v)) {
+                    ok = false;
+                    break;
+                }
+            }
+            left = ok;
+        }
+        if (noZero(s)) {
+            boolean ok = true;
+            for (int i = s.length(); i >= 1; i--) {
+                int v = Integer.parseInt(s.substring(0, i));
+                if (!isPrime(v)) {
+                    ok = false;
+                    break;
+                }
+            }
+            right = ok;
+        }
+        if (left && right)
+            System.out.println("both");
+        else if (left)
+            System.out.println("left");
+        else if (right)
+            System.out.println("right");
+        else
+            System.out.println("false");
+        in.close();
+    }
+}

作业/作业/刘航宇-day1/第一题/DivideNum.java

@@ -0,0 +1,18 @@
+import java.util.Scanner;
+
+public class DivideNum {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int num = 0;
+        System.out.println("请输入一个非负三位整数：");
+        num = in.nextInt();
+        int hundreds = num / 100;
+        int tens = (num / 10) % 10;
+        int units = num % 10;
+        System.out.println(hundreds);
+        System.out.println(tens);
+        System.out.println(units);
+        
+        in.close();
+    }
+}

作业/作业/刘航宇-day1/第二题/ca.java

@@ -0,0 +1,14 @@
+import java.util.Scanner;
+
+public class ca {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        double r = 0;
+        r= in.nextDouble();
+        double S_fang = r * r;
+        double S_yuan = 3.14 * (r * r)/4;
+        double S_ca = S_fang - S_yuan;
+        System.out.println("面积差是：" + S_ca);
+        in.close();
+    }
+}

作业/作业/刘航宇-day11/第一题/max.java

@@ -0,0 +1,40 @@
+import java.util.Scanner;
+
+public class max {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        System.out.print("请输入三个整数，以空格分隔: ");
+        int a, b, c;
+        a = in.nextInt();
+        b = in.nextInt();
+        c = in.nextInt();
+
+        int max = a;
+        if (b > max) {
+            max = b;
+        }
+        if (c > max) {
+            max = c;
+        }
+
+        int min = a;
+        if (b < min) {
+            min = b;
+        }
+        if (c < min) {
+            min = c;
+        }
+
+        int result;
+        if (a != max && a != min) {
+            result = a;
+        } else if (b != max && b != min) {
+            result = b;
+        } else {
+            result = c;
+        }
+
+        System.out.println("第二小值是: " + result);
+        in.close();
+    }
+}

作业/作业/刘航宇-day11/第二题/Num.java

@@ -0,0 +1,61 @@
+import java.util.Scanner;
+
+public class Num {
+    private static int min_m(int n, int m) {
+        int result = n - (m * (m - 1) / 2);
+        // 分子≤0 或 无法被m整除 → 不满足条件
+        if (result <= 0 || result % m != 0) {
+            return -1;
+        }
+        // 返回连续序列的首项a（正整数）
+        return result / m;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        System.out.print("请输入n:");
+        int n = in.nextInt();
+
+        // 防止输入错误
+        if (n < 1 || n > 10000) {
+            System.out.println("无符合条件的连续正整数序列");
+            System.out.println("n应该在1-10000之间");
+            in.close();
+            return;
+        }
+
+        boolean found = false;
+        int m = 2;
+        int firstnum = -1;
+
+        // 从m=2开始寻找，找到第一个满足条件的m就停止
+        for (m = 2; m <= 150; m++) {
+            int sum_m = m * (m - 1) / 2;
+            // 如果n小于等于前m-1个数的和，说明m太大
+            if (n <= sum_m) {
+                break;
+            }
+
+            firstnum = min_m(n, m);
+            if (firstnum != -1) {
+                found = true;
+                break;
+            }
+        }
+
+        if (found) {
+            System.out.print(n + "=");
+            for (int i = 0; i < m; i++) {
+                System.out.print(firstnum + i);
+                if (i < m - 1) {
+                    System.out.print("+");
+                }
+            }
+        } 
+        else {
+            System.out.println("无符合条件的连续正整数序列");
+        }
+        
+        in.close();
+    }
+}

作业/作业/刘航宇-day12/第一题/shiyi.java

@@ -0,0 +1,23 @@
+import java.util.Scanner;
+
+public class shiyi {
+    private static int f(int n) {
+        if (n == 1) {
+            return 1;
+        }
+        if (n == 2) {
+            return 1;
+        }
+        return 2*f(n-2)+f(n-1);
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        System.out.print("请输入一个整数n：");
+        int n = in.nextInt();
+        int result = f(n);
+        System.out.println(result);
+
+        in.close();
+    }
+}

作业/作业/刘航宇-day12/第二题/perfect.java

@@ -0,0 +1,36 @@
+import java.util.Scanner;
+
+public class perfect {
+    private static boolean isPerfect(int n) {
+        if (n <= 1) {
+            return false;
+        }
+
+        int sum = 1;
+        for (int i = 2; i <= Math.sqrt(n); i++) {
+            if (n % i == 0) {
+                sum += i;
+                int other = n / i;
+                if (other != i && other != n) {
+                    sum += other;
+                }
+            }
+        }
+
+        return sum == n;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        System.out.print("请输入一个数字: ");
+        int n = in.nextInt();
+
+        for (int i = 2; i <= n; i++) {
+            if (isPerfect(i)) {
+                System.out.println(i);
+            }
+        }
+        
+        in.close();
+    }
+}

作业/作业/刘航宇-day13/第一题/Circle.java

@@ -0,0 +1,28 @@
+public class Circle {
+    private double r;
+
+    // ! 构造方法，用于初始化半径
+    public Circle(double r) {
+        this.r = r;
+    }
+
+    // ! 计算圆的面积
+    public double GetArea() {
+        return Math.PI * r * r;
+    }
+
+    // ! 计算圆的周长
+    public double GetPerimeter() {
+        return 2 * Math.PI * r;
+    }
+
+    // ! 获取圆的半径
+    public double GetRadius() {
+        return r;
+    }
+
+    // ! 设置圆的半径
+    public void SetRadius(double r) {
+        this.r = r;
+    }
+}

作业/作业/刘航宇-day13/第一题/Main.java

@@ -0,0 +1,22 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        System.out.print("请输入圆的半径: ");
+        String line = in.nextLine();
+
+        // 兼容终端管道可能插入的不可见字符，保留数字和符号
+        line = line.replaceAll("[^0-9.+-]", "");
+        double radius = Double.parseDouble(line);
+        
+        // 创建一个半径可输入的圆对象
+        Circle circle = new Circle(radius);
+
+        // 输出圆的面积和周长
+        System.out.printf("圆的面积: %.2f\n", circle.GetArea());
+        System.out.printf("圆的周长: %.2f\n", circle.GetPerimeter());
+
+        in.close();
+    }
+}

作业/作业/刘航宇-day13/第二题/Employee.java

@@ -0,0 +1,58 @@
+public class Employee {
+    private String name;
+    private String gender;
+    private String birthDate;
+    private double salary;
+
+    // 无参构造方法
+    public Employee() {}
+
+    // 带参构造方法
+    public Employee(String name, String gender, String birthDate, double salary) {
+        this.name = name;
+        this.gender = gender;
+        this.birthDate = birthDate;
+        this.salary = salary;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getGender() {
+        return gender;
+    }
+
+    public void setGender(String gender) {
+        this.gender = gender;
+    }
+
+    public String getBirthDate() {
+        return birthDate;
+    }
+
+    public void setBirthDate(String birthDate) {
+        this.birthDate = birthDate;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public void setSalary(double salary) {
+        this.salary = salary;
+    }
+
+    // 显示员工信息的方法
+    public void displayInfo() {
+        System.out.println("员工信息：");
+        System.out.println("姓名：" + name);
+        System.out.println("性别：" + gender);
+        System.out.println("出生日期：" + birthDate);
+        System.out.printf("工资：%.2f元\n", salary);
+    }
+}

作业/作业/刘航宇-day13/第二题/Main.java

@@ -0,0 +1,31 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        
+        // 创建Employee对象
+        Employee employee = new Employee();
+
+        // 输入员工信息
+        System.out.print("请输入员工姓名：");
+        employee.setName(in.nextLine());
+
+        System.out.print("请输入员工性别：");
+        employee.setGender(in.nextLine());
+
+        System.out.print("请输入出生日期（格式：YYYY-MM-DD）：");
+        employee.setBirthDate(in.nextLine());
+
+        System.out.print("请输入工资：");
+        employee.setSalary(in.nextDouble());
+
+        // 输出空行分隔
+        System.out.println();
+
+        // 输出员工信息
+        employee.displayInfo();
+
+        in.close();
+    }
+}

作业/作业/刘航宇-day14/第一题/Main.java

@@ -0,0 +1,15 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        System.out.print("请输入一个整数（表示秒数）：");
+        int t = in.nextInt();
+        Time time = new Time();
+        time.Set(t);
+        System.out.print("转换后的时间是：");
+        time.Display();
+        
+        in.close();
+    }
+}

作业/作业/刘航宇-day14/第一题/Time.java

@@ -0,0 +1,32 @@
+public class Time {
+    private int h;
+    private int m;
+    private int s;
+
+    // 构造方法
+    public Time() {
+        this.h = 0;
+        this.m = 0;
+        this.s = 0;
+    }
+
+    // 带参构造方法
+    public Time(int h, int m, int s) {
+        this.h = h;
+        this.m = m;
+        this.s = s;
+    }
+
+    // 将时间转换为总秒数
+    public void Set(int t) {
+        this.h = t / 3600;
+        this.m = (t % 3600) / 60;
+        this.s = t % 60;
+    }
+
+    // 显示时间，格式为hh:mm:ss
+    public void Display() {
+        // 使用String.format确保每位数字占两位，不足补零
+        System.out.printf("%02d:%02d:%02d\n", h, m, s);
+    }
+}

作业/作业/刘航宇-day14/第二题/LHY_Compare.java

@@ -0,0 +1,30 @@
+import java.util.Scanner;
+
+public class LHY_Compare {
+    // 重载的compare方法示例
+    public static int compare() {
+        return 0;
+    }
+
+    // 比较两个整数，返回较大的值
+    public static int compare(int a, int b) {
+        if (a > b) {
+            return a;
+        } else if (a < b) {
+            return b;
+        } else {
+            return 0; // 相等时返回0
+        }
+    }
+    
+    // 比较两个字符，返回ASCII码差值的绝对值
+    public static int compare(char a, char b) {
+        return Math.abs(a - b);
+    }
+
+    // 比较两个字符串，返回较大的字符串（按字典序）
+    public static String compare(String a, String b) {
+        return (a.compareTo(b) > 0) ? a : b;
+    }
+
+}

作业/作业/刘航宇-day14/第二题/Main.java

@@ -0,0 +1,30 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+
+        // 读取整数输入
+        System.out.println("请输入两个整数：");
+        int num1 = in.nextInt();
+        int num2 = in.nextInt();
+        // 调用重载方法并输出结果
+        System.out.println(LHY_Compare.compare(num1, num2));
+
+        // 读取字符输入
+        System.out.println("请输入两个字符：");
+        char char1 = in.next().charAt(0);
+        char char2 = in.next().charAt(0);
+        // 调用重载方法并输出结果
+        System.out.println(LHY_Compare.compare(char1, char2));
+
+        // 读取字符串输入
+        System.out.println("请输入两个字符串：");
+        String str1 = in.next();
+        String str2 = in.next();
+        // 调用重载方法并输出结果
+        System.out.println(LHY_Compare.compare(str1, str2));
+        
+        in.close();
+    }
+}

作业/作业/刘航宇-day15/第一题/Airplane.java

@@ -0,0 +1,16 @@
+public class Airplane extends Vehicle {
+    private double flightHeight;
+
+    public Airplane(String name, double flightHeight) {
+        super(name);
+        this.flightHeight = flightHeight;
+    }
+
+    @Override
+    public void travelInfo() {
+        System.out.println("交通工具：飞机（" + name + "）");
+        System.out.println("乘坐信息：飞行高度" + flightHeight + "米，适合长途旅行");
+        System.out.println("特点：速度快，效率高");
+        System.out.println("------------------------");
+    }
+}

作业/作业/刘航宇-day15/第一题/Car.java

@@ -0,0 +1,16 @@
+public class Car extends Vehicle {
+    private int maxSpeed;
+
+    public Car(String name, int maxSpeed) {
+        super(name);
+        this.maxSpeed = maxSpeed;
+    }
+
+    @Override
+    public void travelInfo() {
+        System.out.println("交通工具：汽车（" + name + "）");
+        System.out.println("乘坐信息：最高时速" + maxSpeed + "km/h，适合短途旅行");
+        System.out.println("特点：灵活方便，点对点运输");
+        System.out.println("------------------------");
+    }
+}

作业/作业/刘航宇-day15/第一题/Main.java

@@ -0,0 +1,26 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+
+        Vehicle car = new Car("特斯拉Model S", 250);
+        Vehicle train = new Train("复兴号高铁", 16);
+        Vehicle airplane = new Airplane("波音747", 12500);
+
+        // 调用各交通工具的方法
+        System.out.println("=== 交通工具乘坐信息 ===");
+        System.out.println();
+
+        car.start();
+        car.travelInfo();
+
+        train.start();
+        train.travelInfo();
+
+        airplane.start();
+        airplane.travelInfo();
+        
+        in.close();
+    }
+}

作业/作业/刘航宇-day15/第一题/Train.java

@@ -0,0 +1,17 @@
+public class Train extends Vehicle {
+    private int carriageCount;
+
+    public Train(String name, int carriageCount) {
+        super(name);
+        this.carriageCount = carriageCount;
+    }
+
+    @Override
+    public void travelInfo() {
+        System.out.println("交通工具：火车（" + name + "）");
+        System.out.println("乘坐信息：" + carriageCount + "节车厢，适合中长途旅行");
+        System.out.println("特点：运量大，准时可靠");
+        System.out.println("------------------------");
+    }
+
+}

作业/作业/刘航宇-day15/第一题/Vehicle.java

@@ -0,0 +1,15 @@
+public abstract class Vehicle {
+    public String name;
+
+    public Vehicle(String name) {
+        this.name = name;
+    }
+
+    // 抽象方法，子类必须实现
+    public abstract void travelInfo();
+
+    // 具体方法，子类可以继承
+    public void start() {
+        System.out.println(name + "开始启动...");
+    }
+}

作业/作业/刘航宇-day15/第二题/DbDriver.java

@@ -0,0 +1,5 @@
+public interface DbDriver {
+    void connect(); // 连接数据库方法
+    void executeQuery(); // 执行查询方法
+    void disconnect(); // 断开连接方法
+}

作业/作业/刘航宇-day15/第二题/GoogleDriver.java

@@ -0,0 +1,17 @@
+public class GoogleDriver implements DbDriver {
+    @Override
+    public void connect() {
+        System.out.println("Google云数据库驱动：建立云端连接...");
+    }
+
+    @Override
+    public void executeQuery() {
+        System.out.println("Google云数据库驱动：执行分布式查询");
+    }
+
+    @Override
+    public void disconnect() {
+        System.out.println("Google云数据库驱动：关闭云连接");
+        System.out.println("------------------------");
+    }
+}

作业/作业/刘航宇-day15/第二题/IBMDriver.java

@@ -0,0 +1,17 @@
+public class IBMDriver implements DbDriver {
+    @Override
+    public void connect() {
+        System.out.println("IBM数据库驱动：建立安全连接...");
+    }
+
+    @Override
+    public void executeQuery() {
+        System.out.println("IBM数据库驱动：执行高性能查询操作");
+    }
+
+    @Override
+    public void disconnect() {
+        System.out.println("IBM数据库驱动：安全断开连接");
+        System.out.println("------------------------");
+    }
+}

作业/作业/刘航宇-day15/第二题/Main.java

@@ -0,0 +1,37 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+
+        // 使用接口的多态：同一调用输出不同内容
+        UserDriver userDriver = new UserDriver();
+
+        // 使用接口类型声明变量
+        IBMDriver IBMDriver = new IBMDriver();
+        GoogleDriver GoogleDriver = new GoogleDriver();
+
+        // 使用IBM驱动
+        System.out.println("=== 测试IBM数据库驱动 ===");
+        userDriver.setDriver(IBMDriver);
+        userDriver.useDriver();
+
+        // 使用Google驱动
+        System.out.println("=== 测试Google数据库驱动 ===");
+        userDriver.setDriver(GoogleDriver);
+        userDriver.useDriver();
+
+        // 演示多态特性
+        System.out.println("=== 多态特性演示 ===");
+        DbDriver[] drivers = {
+            new IBMDriver(),
+            new GoogleDriver()
+        };
+        for (DbDriver driver : drivers) {
+            userDriver.setDriver(driver);
+            userDriver.useDriver();
+        }
+
+        in.close();
+    }
+}

作业/作业/刘航宇-day15/第二题/UserDriver.java

@@ -0,0 +1,19 @@
+public class UserDriver {
+    private DbDriver driver;
+
+    // 设置使用的驱动
+    public void setDriver(DbDriver driver) {
+        this.driver = driver;
+    }
+
+    // 使用驱动执行操作
+    public void useDriver() {
+        if (driver != null) {
+            driver.connect();
+            driver.executeQuery();
+            driver.disconnect();
+        } else {
+            System.out.println("未设置数据库驱动！");
+        }
+    }
+}

作业/作业/刘航宇-day16/第一题/Main.java

@@ -0,0 +1,24 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+
+        String input = in.nextLine(); // 读取一行输入
+        int count = 0;
+        
+        // 遍历字符串中的每个字符
+        for (int i = 0; i < input.length(); i++) {
+            char c = input.charAt(i);
+            if (Character.isDigit(c)) {
+                // 检查字符是否为数字
+                count++;
+            }
+        }
+        
+        // 输出数字字符个数
+        System.out.println(count); 
+
+        in.close();
+    }
+}

作业/作业/刘航宇-day17/第一题/Main.java

@@ -0,0 +1,45 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Arrays;
+
+public class Main {
+    public static void main(String[] args) {
+        String s = "A1B2C3D4E5F6G7H8";
+
+        int[] nums = extractInts(s);
+        String[] letters = extractLetters(s);
+
+        System.out.println(Arrays.toString(nums));
+        System.out.println(Arrays.toString(letters));
+    }
+
+    // 提取数字到 int[]
+    public static int[] extractInts(String s) {
+        List<Integer> list = new ArrayList<>();
+        // 遍历字符串，提取数字字符
+        for (int i = 0; i < s.length(); i++) {
+            char c = s.charAt(i);
+            if (Character.isDigit(c)) {
+                list.add(c - '0');
+            }
+        }
+        // 将 List<Integer> 转换为 int[]
+        int[] arr = new int[list.size()];
+        for (int i = 0; i < list.size(); i++)
+            arr[i] = list.get(i);
+        return arr;
+    }
+
+    // 提取字母到 String[]
+    public static String[] extractLetters(String s) {
+        List<String> list = new ArrayList<>();
+        // 遍历字符串，提取字母字符
+        for (int i = 0; i < s.length(); i++) {
+            char c = s.charAt(i);
+            if (Character.isLetter(c)) {
+                list.add(String.valueOf(c).toUpperCase());
+            }
+        }
+        return list.toArray(new String[0]);
+    }
+}

作业/作业/刘航宇-day17/第二题/Main.java

@@ -0,0 +1,21 @@
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public class Main {
+    // 使用 Map 统计字符串数组中各元素出现次数
+    public static Map<String, Integer> count(String[] arr) {
+        Map<String, Integer> freq = new LinkedHashMap<>(); // 保持键的插入顺序
+        for (String s : arr) {
+            freq.put(s, freq.getOrDefault(s, 0) + 1);
+        }
+        return freq;
+    }
+
+    public static void main(String[] args) {
+        String[] input = { "a", "b", "a", "b", "c", "a", "b", "c", "b" };
+        Map<String, Integer> result = count(input);
+        System.out.println("输入: " + Arrays.toString(input));
+        System.out.println("统计结果: " + result); // 期望 {a=3, b=4, c=2}
+    }
+}

作业/作业/刘航宇-day18/第一题/Complex.java

@@ -0,0 +1,25 @@
+public class Complex {
+    public int real;
+    public int imag;
+
+    public Complex(int real, int imag) {
+        this.real = real;
+        this.imag = imag;
+    }
+
+    public Complex add(Complex other) {
+        return new Complex(this.real + other.real, this.imag + other.imag);
+    }
+
+    public Complex sub(Complex other) {
+        return new Complex(this.real - other.real, this.imag - other.imag);
+    }
+
+    // 输出形如 8+6i 或 8-6i
+    @Override
+    public String toString() {
+        String sign = imag >= 0 ? "+" : "-";
+        int absImag = Math.abs(imag);
+        return real + sign + absImag + "i";
+    }
+}

作业/作业/刘航宇-day18/第一题/ComplexCalc.java

@@ -0,0 +1,87 @@
+import java.util.Scanner;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ComplexCalc {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String line = in.nextLine().trim();
+        in.close();
+
+        // 支持三种输入：
+        // 1) "3 2 + 5 4"  -> (3+2i) op (5+4i)
+        // 2) "32 + 54"    -> (3+2i) op (5+4i)
+        // 3) "3+2i + 5+4i" -> 常见复数格式（运算符两侧有空格）
+
+        ParseResult pr = parse(line);
+        if (pr == null) {
+            System.out.println("输入格式不正确");
+            return;
+        }
+
+        Complex a = pr.left;
+        Complex b = pr.right;
+        Complex res = pr.op == '+' ? a.add(b) : a.sub(b);
+        System.out.println(res.toString());
+    }
+
+    static class ParseResult {
+        Complex left;
+        Complex right;
+        char op; // '+' or '-'
+        ParseResult(Complex l, Complex r, char o) { left = l; right = r; op = o; }
+    }
+
+    private static ParseResult parse(String line) {
+        // 尝试格式1：a b op c d
+        String[] tokens = line.split("\\s+");
+        if (tokens.length == 5 && isSign(tokens[2])) {
+            try {
+                int r1 = Integer.parseInt(tokens[0]);
+                int i1 = Integer.parseInt(tokens[1]);
+                int r2 = Integer.parseInt(tokens[3]);
+                int i2 = Integer.parseInt(tokens[4]);
+                return new ParseResult(new Complex(r1, i1), new Complex(r2, i2), tokens[2].charAt(0));
+            } catch (NumberFormatException ignored) {}
+        }
+
+        // 尝试格式2：ab op cd（各为两个数字）
+        if (tokens.length == 3 && isSign(tokens[1]) && tokens[0].matches("\\d{2}") && tokens[2].matches("\\d{2}")) {
+            int r1 = tokens[0].charAt(0) - '0';
+            int i1 = tokens[0].charAt(1) - '0';
+            int r2 = tokens[2].charAt(0) - '0';
+            int i2 = tokens[2].charAt(1) - '0';
+            return new ParseResult(new Complex(r1, i1), new Complex(r2, i2), tokens[1].charAt(0));
+        }
+
+        // 尝试格式3：a+bi op c+di（运算符两侧必须有空格）
+        if (line.contains(" + ") || line.contains(" - ")) {
+            char op = line.contains(" + ") ? '+' : '-';
+            String[] parts = line.split("\\s+[+\\-]\\s+");
+            if (parts.length == 2) {
+                Complex left = parseAPlusBi(parts[0]);
+                Complex right = parseAPlusBi(parts[1]);
+                if (left != null && right != null) {
+                    return new ParseResult(left, right, op);
+                }
+            }
+        }
+        return null;
+    }
+
+    private static boolean isSign(String s) {
+        return s.length() == 1 && (s.charAt(0) == '+' || s.charAt(0) == '-');
+    }
+
+    private static Complex parseAPlusBi(String s) {
+        s = s.trim();
+        Matcher m = Pattern.compile("^([+-]?\\d+)\\s*([+\\-])\\s*([+-]?\\d+)i$").matcher(s);
+        if (m.matches()) {
+            int r = Integer.parseInt(m.group(1));
+            int sign = m.group(2).charAt(0) == '-' ? -1 : 1;
+            int i = sign * Integer.parseInt(m.group(3));
+            return new Complex(r, i);
+        }
+        return null;
+    }
+}

作业/作业/刘航宇-day18/第二题/DateApp.java

@@ -0,0 +1,18 @@
+import java.util.Scanner;
+
+public class DateApp {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String line = in.nextLine().trim(); // 形如 2020-10-10
+        in.close();
+
+        String[] parts = line.split("-");
+        int y = Integer.parseInt(parts[0]);
+        int m = Integer.parseInt(parts[1]);
+        int d = Integer.parseInt(parts[2]);
+
+        MyDate date = new MyDate();
+        date.set(y, m, d);
+        date.print();
+    }
+}

作业/作业/刘航宇-day18/第二题/MyDate.java

@@ -0,0 +1,16 @@
+public class MyDate {
+    private int year;
+    private int month;
+    private int day;
+
+    public void set(int year, int month, int day) {
+        this.year = year;
+        this.month = month;
+        this.day = day;
+    }
+
+    public void print() {
+        System.out.println("输出重置后的时间：");
+        System.out.println(year + ":" + month + ":" + day);
+    }
+}

作业/作业/刘航宇-day19/第一题/Main.java

@@ -0,0 +1,37 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+
+        // 5x5
+        int Shuzu[][] = new int[5][5];
+        for (int i = 0; i < 5; i++) {
+            for (int j = 0; j < 5; j++) {
+                Shuzu[i][j] = in.nextInt();
+            }
+        }
+
+        // m n
+        int m, n;
+        m = in.nextInt();
+        n = in.nextInt();
+
+        //
+        int temp[]=new int[5];
+        for (int j = 0; j < 5; j++) {
+            temp[j] = Shuzu[m][j];
+            Shuzu[m][j] = Shuzu[n][j];
+            Shuzu[n][j] = temp[j];
+        }
+
+        for (int i = 0; i < 5; i++) {
+            for (int j = 0; j < 5; j++) {
+                System.out.print(Shuzu[i][j] + " ");
+            }
+            System.out.println();
+        }
+
+        in.close();
+    }
+}

作业/作业/刘航宇-day19/第二题/DateApp.java

@@ -0,0 +1,18 @@
+import java.util.Scanner;
+
+public class DateApp {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String line = in.nextLine().trim(); // 形如 2020-10-10
+        in.close();
+
+        String[] parts = line.split("-");
+        int y = Integer.parseInt(parts[0]);
+        int m = Integer.parseInt(parts[1]);
+        int d = Integer.parseInt(parts[2]);
+
+        MyDate date = new MyDate();
+        date.set(y, m, d);
+        date.print();
+    }
+}

作业/作业/刘航宇-day19/第二题/MyDate.java

@@ -0,0 +1,16 @@
+public class MyDate {
+    private int year;
+    private int month;
+    private int day;
+
+    public void set(int year, int month, int day) {
+        this.year = year;
+        this.month = month;
+        this.day = day;
+    }
+
+    public void print() {
+        System.out.println("输出重置后的时间：");
+        System.out.println(year + ":" + month + ":" + day);
+    }
+}

作业/作业/刘航宇-day2/第一题/MaxNum.java

@@ -0,0 +1,36 @@
+import java.util.Scanner;
+
+public class MaxNum {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int a = in.nextInt();
+        int b = in.nextInt();
+        int c = in.nextInt();
+        int max = 0;
+        if (a>=b)
+        {
+            if (a>=c)
+            {
+                max = a;
+            }
+            else
+            {
+                max = c;
+            }
+        }
+        else
+        {
+            if (b>=c)
+            {
+                max = b;
+            }
+            else
+            {
+                max = c;
+            }
+        }
+        System.out.println("max="+max);
+        in.close();
+    }
+    
+}

作业/作业/刘航宇-day2/第二题/DaFen.java

@@ -0,0 +1,29 @@
+import java.util.Scanner;
+
+public class DaFen {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        int score = 0;
+        if (n<0 || n>40)
+        {
+            System.out.println("做对题目数量有误");
+        }
+        else {
+            if (n <= 10) {
+                score = n * 6;
+                System.out.println("score=" + score);
+            }
+            if (n > 10 && n <= 20) {
+                score = 60 + (n - 10) * 2;
+                System.out.println("score=" + score);
+            }
+            if (n > 20) {
+                score = 80 + (n - 20);
+                System.out.println("score=" + score);
+            }
+        }
+        in.close();
+    }
+    
+}

作业/作业/刘航宇-day20/第一题/Main.java

@@ -0,0 +1,64 @@
+import java.util.Scanner;
+
+public class Main {
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int rows = 5, cols = 5; // 可灵活调整矩阵大小
+        int[][] matrix = new int[rows][cols];
+
+        System.out.println("请输入" + rows + "×" + cols + "二维数组的元素：");
+        for (int i = 0; i < rows; i++) {
+            for (int j = 0; j < cols; j++) {
+                matrix[i][j] = in.nextInt();
+            }
+        }
+
+        findSaddlePoints(matrix);
+        in.close();
+    }
+
+    public static void findSaddlePoints(int[][] matrix) {
+        int rows = matrix.length;
+        int cols = matrix[0].length;
+        boolean found = false;
+
+        // 预计算每行的最大值
+        int[] rowMaxs = new int[rows];
+        for (int i = 0; i < rows; i++) {
+            int max = matrix[i][0];
+            for (int j = 1; j < cols; j++) {
+                if (matrix[i][j] > max) {
+                    max = matrix[i][j];
+                }
+            }
+            rowMaxs[i] = max;
+        }
+
+        // 预计算每列的最小值
+        int[] colMins = new int[cols];
+        for (int j = 0; j < cols; j++) {
+            int min = matrix[0][j];
+            for (int i = 1; i < rows; i++) {
+                if (matrix[i][j] < min) {
+                    min = matrix[i][j];
+                }
+            }
+            colMins[j] = min;
+        }
+
+        // 查找鞍点：行最大值且列最小值
+        for (int i = 0; i < rows; i++) {
+            for (int j = 0; j < cols; j++) {
+                if (matrix[i][j] == rowMaxs[i] && matrix[i][j] == colMins[j]) {
+                    System.out.println("鞍点位置: (" + i + ", " + j + "), 值: " + matrix[i][j]);
+                    found = true;
+                }
+            }
+        }
+
+        if (!found) {
+            System.out.println("未找到鞍点");
+        }
+    }
+}

作业/作业/刘航宇-day20/第三题/Main.java

@@ -0,0 +1,48 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        // 存储26个字母的出现次数
+        int[] frequency = new int[26];
+        int maxFrequency = 0;
+
+        // 读取4行文本并统计频率
+        for (int i = 0; i < 4; i++) {
+            String line = scanner.nextLine().toUpperCase();
+            for (char c : line.toCharArray()) {
+                if (c >= 'A' && c <= 'Z') {
+                    int index = c - 'A';
+                    frequency[index]++;
+                    if (frequency[index] > maxFrequency) {
+                        maxFrequency = frequency[index];
+                    }
+                }
+            }
+        }
+
+        // 绘制垂直直方图
+        for (int row = maxFrequency; row > 0; row--) {
+            StringBuilder line = new StringBuilder();
+            for (int i = 0; i < 26; i++) {
+                if (frequency[i] >= row) {
+                    line.append("* ");
+                } else {
+                    line.append("  ");
+                }
+            }
+            // 去除行尾空格后输出
+            System.out.println(line.toString().replaceAll("\\s+$", ""));
+        }
+
+        // 输出字母行
+        StringBuilder alphabetLine = new StringBuilder();
+        for (char c = 'A'; c <= 'Z'; c++) {
+            alphabetLine.append(c).append(" ");
+        }
+        System.out.println(alphabetLine.toString().trim());
+
+        scanner.close();
+    }
+}

作业/作业/刘航宇-day20/第二题/Main.java

@@ -0,0 +1,30 @@
+import java.util.Arrays;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        // 处理多组测试数据
+        while (scanner.hasNextInt()) {
+            int n = scanner.nextInt();
+            int[] numbers = new int[n];
+
+            // 读取n个整数
+            for (int i = 0; i < n; i++) {
+                numbers[i] = scanner.nextInt();
+            }
+
+            // 对数组进行排序
+            Arrays.sort(numbers);
+
+            // 输出排序结果
+            for (int i = 0; i < n; i++) {
+                System.out.print(numbers[i] + " ");
+            }
+            System.out.println(); // 换行
+        }
+
+        scanner.close();
+    }
+}

作业/作业/刘航宇-day21/第一题/Main.java

@@ -0,0 +1,28 @@
+import java.util.Scanner;
+
+public class Main {
+    public static boolean isPrime(int number) {
+        if (number <= 1) {
+            return false;
+        }
+        for (int i = 2; i <= Math.sqrt(number); i++) {
+            if (number % i == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        System.out.print("请输入一个整数：");
+        int number = in.nextInt();
+        if (isPrime(number)) {
+            System.out.println(number + "是素数");
+        } else {
+            System.out.println(number + "不是素数");
+        }
+        
+        in.close();
+    }
+}

作业/作业/刘航宇-day21/第三题/Main.java

@@ -0,0 +1,20 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        in.close();
+
+        long res = 1L;
+        for (int i = 2; i <= n; i++) {
+            res *= i;
+            while (res % 10 == 0) {
+                res /= 10; // 去除产生的0
+            }
+            res %= 10000000L; // 保留足够位数避免溢出
+        }
+
+        System.out.println(res % 10);
+    }
+}

作业/作业/刘航宇-day21/第二题/InsertSorted.java

@@ -0,0 +1,33 @@
+import java.util.Scanner;
+
+public class InsertSorted {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        int[] arr = new int[10]; // 容纳插入后的10个元素
+        for (int i = 0; i < 9; i++) {
+            if (sc.hasNextInt()) {
+                arr[i] = sc.nextInt();
+            }
+        }
+        int x = sc.nextInt(); // 待插入的数字
+        sc.close();
+
+        int pos = 9; // 默认插到末尾
+        for (int i = 0; i < 9; i++) {
+            if (x <= arr[i]) {
+                pos = i;
+                break;
+            }
+        }
+
+        for (int i = 9; i > pos; i--) {
+            arr[i] = arr[i - 1];
+        }
+        arr[pos] = x;
+
+        for (int i = 0; i < 10; i++) {
+            System.out.println(arr[i]);
+        }
+    }
+}

作业/作业/刘航宇-day22/第一题/Main.java

@@ -0,0 +1,27 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String n = in.next();
+        int s = in.nextInt();
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < n.length(); i++) {
+            char c = n.charAt(i);
+            while (s > 0 && sb.length() > 0 && sb.charAt(sb.length() - 1) > c) {
+                sb.deleteCharAt(sb.length() - 1);
+                s--;
+            }
+            sb.append(c);
+        }
+        if (s > 0) {
+            int newLen = Math.max(0, sb.length() - s);
+            sb.setLength(newLen);
+        }
+        int idx = 0;
+        while (idx < sb.length() && sb.charAt(idx) == '0') idx++;
+        String res = idx == sb.length() ? "0" : sb.substring(idx);
+        System.out.println(res);
+        in.close();
+    }
+}

作业/作业/刘航宇-day23/第一题/Main.java

@@ -0,0 +1,34 @@
+import java.util.Scanner;
+
+public class Main {
+    static int gcd(int a, int b) {
+        a = Math.abs(a);
+        b = Math.abs(b);
+        while (b != 0) {
+            int t = a % b;
+            a = b;
+            b = t;
+        }
+        return a;
+    }
+
+    static long lcm(int a, int b) {
+        if (a == 0 || b == 0) return 0L;
+        int g = gcd(a, b);
+        long x = (long) a / g;
+        long y = (long) b;
+        long res = x * y;
+        if (res < 0) res = -res;
+        return res;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int a = in.nextInt();
+        int b = in.nextInt();
+        int g = gcd(a, b);
+        long l = lcm(a, b);
+        System.out.println(g + " " + l);
+        in.close();
+    }
+}

作业/作业/刘航宇-day23/第三题/Main.java

@@ -0,0 +1,32 @@
+import java.util.Scanner;
+import java.math.BigInteger;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int N = in.nextInt();
+        int K = in.nextInt();
+        String s = in.next();
+        BigInteger[][] dp = new BigInteger[N + 1][K + 2];
+        for (int i = 1; i <= N; i++) {
+            dp[i][1] = new BigInteger(s.substring(0, i));
+        }
+        for (int p = 2; p <= K + 1; p++) {
+            for (int i = p; i <= N; i++) {
+                BigInteger best = null;
+                for (int j = p - 1; j <= i - 1; j++) {
+                    if (dp[j][p - 1] == null)
+                        continue;
+                    BigInteger seg = new BigInteger(s.substring(j, i));
+                    BigInteger cand = dp[j][p - 1].multiply(seg);
+                    if (best == null || cand.compareTo(best) > 0)
+                        best = cand;
+                }
+                dp[i][p] = best;
+            }
+        }
+        BigInteger ans = dp[N][K + 1];
+        System.out.println(ans == null ? "0" : ans.toString());
+        in.close();
+    }
+}

作业/作业/刘航宇-day23/第二题/Main.java

@@ -0,0 +1,16 @@
+import java.util.Scanner;
+
+public class Main {
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        final double PI = 3.1415;
+        for (int i = 0; i < n; i++) {
+            double r = in.nextDouble();
+            double area = PI * r * r;
+            System.out.printf("%.6f\n", area);
+        }
+        in.close();
+    }
+}

作业/作业/刘航宇-day24/第一题/Main.java

@@ -0,0 +1,19 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        int[] a = new int[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = in.nextInt();
+        }
+        int m = in.nextInt();
+        int cnt = 0;
+        for (int i = 0; i < n; i++) {
+            if (a[i] == m) cnt++;
+        }
+        System.out.println(cnt);
+        in.close();
+    }
+}

作业/作业/刘航宇-day24/第三题/Main.java

@@ -0,0 +1,33 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        boolean found = false;
+        for (int a = 1; a <= 9; a++) {
+            for (int b = 0; b <= 9; b++) {
+                for (int c = 0; c <= 9; c++) {
+                    if (2 * a + 2 * b + c == n) {
+                        int x = a * 10000 + b * 1000 + c * 100 + b * 10 + a;
+                        System.out.println(x);
+                        found = true;
+                    }
+                }
+            }
+        }
+        for (int a = 1; a <= 9; a++) {
+            for (int b = 0; b <= 9; b++) {
+                for (int c = 0; c <= 9; c++) {
+                    if (2 * (a + b + c) == n) {
+                        int y = a * 100000 + b * 10000 + c * 1000 + c * 100 + b * 10 + a;
+                        System.out.println(y);
+                        found = true;
+                    }
+                }
+            }
+        }
+        if (!found) System.out.println(-1);
+        in.close();
+    }
+}

作业/作业/刘航宇-day24/第二题/Main.java

@@ -0,0 +1,23 @@
+import java.util.Scanner;
+import java.util.Arrays;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        while (in.hasNextInt()) {
+            int N = in.nextInt();
+            if (N == 0) break;
+            int[] req = new int[N];
+            for (int i = 0; i < N; i++) {
+                int voters = in.nextInt();
+                req[i] = voters / 2 + 1;
+            }
+            Arrays.sort(req);
+            int need = N / 2 + 1;
+            int sum = 0;
+            for (int i = 0; i < need; i++) sum += req[i];
+            System.out.println(sum);
+        }
+        in.close();
+    }
+}

作业/作业/刘航宇-day25/第一题/Main.java

@@ -0,0 +1,14 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        int f = 0;
+        for (int i = 2; i <= n; i++) {
+            f = (f + 3) % i;
+        }
+        System.out.println(f + 1);
+        in.close();
+    }
+}

作业/作业/刘航宇-day25/第三题/Main.java

@@ -0,0 +1,21 @@
+import java.util.Scanner;
+import java.math.BigInteger;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = Integer.parseInt(in.next());
+        if (n == 0) {
+            System.out.println(0);
+            in.close();
+            return;
+        }
+        BigInteger tenPow = BigInteger.TEN.pow(n - 1);
+        BigInteger eightPow = BigInteger.valueOf(8).pow(n - 1);
+        BigInteger part1 = BigInteger.valueOf(9).multiply(tenPow);
+        BigInteger part2 = BigInteger.valueOf(7).multiply(eightPow);
+        BigInteger res = part1.add(part2).divide(BigInteger.valueOf(2));
+        System.out.println(res.toString());
+        in.close();
+    }
+}

作业/作业/刘航宇-day25/第二题/Main.java

@@ -0,0 +1,38 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        long s1 = 0, s2 = 0, s3 = 0;
+        String bestId = "";
+        String bestName = "";
+        int ba = 0, bb = 0, bc = 0;
+        int best = -1;
+        for (int i = 0; i < n; i++) {
+            String id = in.next();
+            String name = in.next();
+            int a = in.nextInt();
+            int b = in.nextInt();
+            int c = in.nextInt();
+            s1 += a;
+            s2 += b;
+            s3 += c;
+            int tot = a + b + c;
+            if (tot > best) {
+                best = tot;
+                bestId = id;
+                bestName = name;
+                ba = a;
+                bb = b;
+                bc = c;
+            }
+        }
+        int avg1 = (int) (s1 / n);
+        int avg2 = (int) (s2 / n);
+        int avg3 = (int) (s3 / n);
+        System.out.println(avg1 + " " + avg2 + " " + avg3);
+        System.out.println(bestId + " " + bestName + " " + ba + " " + bb + " " + bc);
+        in.close();
+    }
+}

作业/作业/刘航宇-day26/第一题/Main.java

@@ -0,0 +1,37 @@
+import java.util.Scanner;
+import java.util.ArrayList;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int a = in.nextInt();
+        String n = in.next();
+        int b = in.nextInt();
+        long value = 0L;
+        for (int i = 0; i < n.length(); i++) {
+            char ch = n.charAt(i);
+            int v;
+            if (ch >= '0' && ch <= '9') v = ch - '0';
+            else if (ch >= 'a' && ch <= 'f') v = ch - 'a' + 10;
+            else if (ch >= 'A' && ch <= 'F') v = ch - 'A' + 10;
+            else v = 0;
+            value = value * a + v;
+        }
+        if (value == 0) {
+            System.out.println("0");
+            in.close();
+            return;
+        }
+        ArrayList<Character> digits = new ArrayList<>();
+        while (value > 0) {
+            int r = (int)(value % b);
+            char d = (char)(r < 10 ? ('0' + r) : ('A' + (r - 10)));
+            digits.add(d);
+            value /= b;
+        }
+        StringBuilder out = new StringBuilder();
+        for (int i = digits.size() - 1; i >= 0; i--) out.append(digits.get(i));
+        System.out.println(out.toString());
+        in.close();
+    }
+}

作业/作业/刘航宇-day27/第一题/Main.java

@@ -0,0 +1,32 @@
+import java.util.Scanner;
+
+public class Main {
+    static boolean isPrime(int x) {
+        if (x < 2) return false;
+        if (x % 2 == 0) return x == 2;
+        for (int i = 3; i * i <= x; i += 2) {
+            if (x % i == 0) return false;
+        }
+        return true;
+    }
+
+    static boolean isPalin(int x) {
+        String s = Integer.toString(x);
+        int i = 0, j = s.length() - 1;
+        while (i < j) {
+            if (s.charAt(i++) != s.charAt(j--)) return false;
+        }
+        return true;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        int cnt = 0;
+        for (int i = 11; i <= n; i++) {
+            if (isPrime(i) && isPalin(i)) cnt++;
+        }
+        System.out.println(cnt);
+        in.close();
+    }
+}

作业/作业/刘航宇-day27/第三题/Main.java

@@ -0,0 +1,15 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int[] h = new int[10];
+        for (int i = 0; i < 10; i++) h[i] = in.nextInt();
+        int reach = in.nextInt();
+        int limit = reach + 30;
+        int count = 0;
+        for (int i = 0; i < 10; i++) if (h[i] <= limit) count++;
+        System.out.println(count);
+        in.close();
+    }
+}