更新

exercise/src/Main.java

@@ -1,59 +1,10 @@
 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");
+        int n = in.nextInt();
+        System.out.println(n % 3 == 0 ? "hua" : "ming");
         in.close();
     }
 }

作业/作业/刘航宇-day35/第一题/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);
+        String s = in.next();
+        int[] cnt = new int[10];
+        for (int i = 0; i < s.length(); i++)
+            cnt[s.charAt(i) - '0']++;
+        StringBuilder out = new StringBuilder(s.length());
+        for (int d = 1; d <= 9; d++) {
+            for (int k = 0; k < cnt[d]; k++)
+                out.append((char) ('0' + d));
+        }
+        for (int k = 0; k < cnt[0]; k++)
+            out.append('0');
+        System.out.println(out.toString());
+        in.close();
+    }
+}

作业/作业/刘航宇-day35/第三题/Main.java

@@ -0,0 +1,30 @@
+import java.util.Scanner;
+
+public class Main {
+    static long phi(long n) {
+        long res = n;
+        long x = n;
+        for (long p = 2; p * p <= x; p++) {
+            if (x % p == 0) {
+                while (x % p == 0)
+                    x /= p;
+                res = res / p * (p - 1);
+            }
+        }
+        if (x > 1)
+            res = res / x * (x - 1);
+        return res;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        long n = in.nextLong();
+        long ans = 0;
+        if (n > 1) {
+            long ph = phi(n);
+            ans = (n - 1) - ph;
+        }
+        System.out.println(ans);
+        in.close();
+    }
+}

作业/作业/刘航宇-day35/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 = Integer.parseInt(in.nextLine().trim());
+        String[] arr = new String[n];
+        for (int i = 0; i < n; i++)
+            arr[i] = in.nextLine();
+        if (n == 0) {
+            System.out.println("");
+            in.close();
+            return;
+        }
+        String first = arr[0];
+        boolean[] used = new boolean[65536];
+        StringBuilder out = new StringBuilder();
+        for (int i = 0; i < first.length(); i++) {
+            char c = first.charAt(i);
+            int idx = c;
+            if (used[idx])
+                continue;
+            boolean ok = true;
+            for (int k = 1; k < n; k++) {
+                if (arr[k].indexOf(c) == -1) {
+                    ok = false;
+                    break;
+                }
+            }
+            if (ok) {
+                out.append(c);
+                used[idx] = true;
+            }
+        }
+        System.out.println(out.toString());
+        in.close();
+    }
+}

作业/作业/刘航宇-day36/第一题/Main.java

@@ -0,0 +1,34 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String text = in.nextLine();
+        String broken = in.nextLine();
+        boolean[] bad = new boolean[26];
+        for (int i = 0; i < broken.length(); i++)
+            bad[broken.charAt(i) - 'a'] = true;
+        int count = 0;
+        boolean inWord = false;
+        boolean wordHasBad = false;
+        for (int i = 0; i < text.length(); i++) {
+            char ch = text.charAt(i);
+            if (ch == ' ') {
+                if (inWord) {
+                    if (!wordHasBad)
+                        count++;
+                    inWord = false;
+                    wordHasBad = false;
+                }
+            } else {
+                inWord = true;
+                if (bad[ch - 'a'])
+                    wordHasBad = true;
+            }
+        }
+        if (inWord && !wordHasBad)
+            count++;
+        System.out.println(count);
+        in.close();
+    }
+}

作业/作业/刘航宇-day36/第三题/Main.java

@@ -0,0 +1,34 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String text = in.nextLine();
+        String broken = in.nextLine();
+        boolean[] bad = new boolean[26];
+        for (int i = 0; i < broken.length(); i++)
+            bad[broken.charAt(i) - 'a'] = true;
+        int count = 0;
+        boolean inWord = false;
+        boolean wordHasBad = false;
+        for (int i = 0; i < text.length(); i++) {
+            char ch = text.charAt(i);
+            if (ch == ' ') {
+                if (inWord) {
+                    if (!wordHasBad)
+                        count++;
+                    inWord = false;
+                    wordHasBad = false;
+                }
+            } else {
+                inWord = true;
+                if (bad[ch - 'a'])
+                    wordHasBad = true;
+            }
+        }
+        if (inWord && !wordHasBad)
+            count++;
+        System.out.println(count);
+        in.close();
+    }
+}

作业/作业/刘航宇-day36/第二题/Main.java

@@ -0,0 +1,34 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String text = in.nextLine();
+        String broken = in.nextLine();
+        boolean[] bad = new boolean[26];
+        for (int i = 0; i < broken.length(); i++)
+            bad[broken.charAt(i) - 'a'] = true;
+        int count = 0;
+        boolean inWord = false;
+        boolean wordHasBad = false;
+        for (int i = 0; i < text.length(); i++) {
+            char ch = text.charAt(i);
+            if (ch == ' ') {
+                if (inWord) {
+                    if (!wordHasBad)
+                        count++;
+                    inWord = false;
+                    wordHasBad = false;
+                }
+            } else {
+                inWord = true;
+                if (bad[ch - 'a'])
+                    wordHasBad = true;
+            }
+        }
+        if (inWord && !wordHasBad)
+            count++;
+        System.out.println(count);
+        in.close();
+    }
+}

作业/作业/刘航宇-day37/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);
+        long n1 = in.nextLong();
+        long n2 = in.nextLong();
+        long l = Math.min(n1, n2), r = Math.max(n1, n2);
+        int[] perfects = {6, 28, 496, 8128, 33550336};
+        int cnt = 0;
+        for (int x : perfects) if (x >= l && x <= r) cnt++;
+        System.out.println(cnt);
+        in.close();
+    }
+}

作业/作业/刘航宇-day37/第三题/Main.java

@@ -0,0 +1,10 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        System.out.println(n % 3 == 0 ? "hua" : "ming");
+        in.close();
+    }
+}

作业/作业/刘航宇-day37/第二题/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);
+        long n = in.nextLong();
+        long cnt = 0;
+        for (long x = 13; x <= n; x += 13) {
+            if (String.valueOf(x).contains("13")) cnt++;
+        }
+        System.out.println(cnt);
+        in.close();
+    }
+}