1、明明的随机数

https://www.lanqiao.cn/problems/539/learning/

解法：暴力

import java.util.Scanner;
import java.util.Arrays;
// 1:无需package
// 2: 类名必须Main, 不可修改

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        //在此输入您的代码...
        int n = scan.nextInt();
        int[] array = new int[n];
        for(int i = 0; i < n; i++) {
          array[i] = scan.nextInt();
        }
        int[] num = new int[n];
        int index = 0;
        for(int j = 0 ; j < n ; j++) {
          boolean junge = false;
          for(int k = 0; k < index; k++) {
            if(num[k] == array[j]) {
              junge = true;
              break;
            }
          }
          if(junge == false) {
            num[index ] = array[j];
            index++;
          }
        }
        Arrays.sort(num);
        System.out.println(index);
        for(int m = n-index ; m< n ; m++) {
          System.out.print(num[m] + " ");
        }
        scan.close();
    }
}

注意：最后打印的时候要从n-index开始，因为排序后前面都是0；

2、特殊日期

https://www.lanqiao.cn/problems/2408/learning/

解法：暴力+枚举

import java.util.Scanner;
// 1:无需package
// 2: 类名必须Main, 不可修改

public class Main {
    public static int fun(int num) {
      int sum = 0;
      while(num != 0 ) {
          sum += num % 10;
          num /= 10;
        }
        return sum;
    }
    public static void main(String[] args) {
      int[] day = {0, 31,28,31,30,31,30,31,31,30,31,30,31};
      int count = 0;
      for( int i = 1900 ; i <= 9999 ; i++ ) {
        if((i % 4 == 0 && i % 100 != 0) || i% 400 == 0 ) {
          day[2] = 29;
        }else {
          day[2] = 28;
        }
        for(int j = 1 ; j < 13 ; j++) {
          for(int k = 1 ; k <= day[j] ; k++) {
            if(fun(i) == fun(j) + fun(k)) {
              count++;
            }
          }
        }
      }
      System.out.println(count);
    }
}