更新

作业/作业/刘航宇-day46/第一题/P2981.java

@@ -0,0 +1,20 @@
+import java.util.*;
+
+public class P2981 {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        List<Long> nums = new ArrayList<>();
+        while (in.hasNextLong()) nums.add(in.nextLong());
+        int pos = 0, neg = 0, zero = 0, even = 0, odd = 0;
+        for (long x : nums) {
+            if (x == 0) zero++; else if (x > 0) pos++; else neg++;
+            if ((x & 1) == 0) even++; else odd++;
+        }
+        System.out.println(pos);
+        System.out.println(neg);
+        System.out.println(zero);
+        System.out.println(even);
+        System.out.println(odd);
+        in.close();
+    }
+}

作业/作业/刘航宇-day46/第三题/P2972.java

@@ -0,0 +1,40 @@
+import java.util.*;
+
+public class P2972 {
+    static String trimLeadingZeros(String s) {
+        int i = 0;
+        while (i < s.length() - 1 && s.charAt(i) == '0') i++;
+        return s.substring(i);
+    }
+
+    static String multiplyBy13(String num) {
+        boolean neg = false;
+        int start = 0;
+        if (num.startsWith("-")) { neg = true; start = 1; }
+        String s = num.substring(start);
+        int n = s.length();
+        int carry = 0;
+        StringBuilder sb = new StringBuilder(n + 4);
+        for (int i = n - 1; i >= 0; i--) {
+            int d = s.charAt(i) - '0';
+            int t = d * 13 + carry;
+            sb.append((char)('0' + (t % 10)));
+            carry = t / 10;
+        }
+        while (carry > 0) {
+            sb.append((char)('0' + (carry % 10)));
+            carry /= 10;
+        }
+        String res = sb.reverse().toString();
+        res = trimLeadingZeros(res);
+        if (res.equals("0")) return "0";
+        return neg ? ("-" + res) : res;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        String s = in.hasNext() ? in.next() : "0";
+        System.out.println(multiplyBy13(s));
+        in.close();
+    }
+}

作业/作业/刘航宇-day46/第二题/P2973.java

@@ -0,0 +1,23 @@
+import java.util.*;
+
+public class P2973 {
+    static long modPow(long base, long exp, long mod) {
+        base %= mod;
+        long res = 1 % mod;
+        while (exp > 0) {
+            if ((exp & 1) == 1) res = (res * base) % mod;
+            base = (base * base) % mod;
+            exp >>= 1;
+        }
+        return res;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        long p = in.nextLong();
+        long g = in.nextLong();
+        long a = in.nextLong();
+        System.out.println(modPow(g, a, p));
+        in.close();
+    }
+}