1.4

1.A+B(https://www.acwing.com/problem/content/1/)

 1 import java.util.Scanner;
 2 
 3 public class Main{
 4     public static void main(String [] args){
 5         Scanner sc = new Scanner(System.in);
 6         int a = sc.nextInt(), b = sc.nextInt();
 7         System.out.println(a + b);
 8         
 9     }
10 }

2.差(https://www.acwing.com/problem/content/610/)

 1 import java.util.Scanner;
 2 public class Main{
 3     public static void main(String [] args) {
 4         Scanner sc = new Scanner(System.in);
 5         int a = sc.nextInt();
 6         int b = sc.nextInt();
 7         int c = sc.nextInt();
 8         int d = sc.nextInt();
 9         System.out.printf("DIFERENCA = %d",a*b-c*d);
10     }
11 }

3.两点间的距离(https://www.acwing.com/problem/content/618/)

1 import java.util.*;
2 public class Main{
3     public static void main(String[] args){
4         Scanner sc = new Scanner(System.in);
5         double x1 = sc.nextDouble(), y1 = sc.nextDouble(), x2 = sc.nextDouble(), y2 = sc.nextDouble();
6         System.out.printf("%.4f",Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)));
7     }
8 }

4.钞票(https://www.acwing.com/problem/content/655/)

import java.util.Scanner;
  public class Main{
      public static void main(String [] args){
          Scanner sc = new Scanner(System.in);
          int x = sc.nextInt();
          System.out.println(x);
          int y = x % 100;
          int p = x;
          
          System.out.printf("%d nota(s) de R$ 100,00\n", ((p - y)/100));
          p = y;
          y = y % 50;
          System.out.printf("%d nota(s) de R$ 50,00\n", ((p - y)/50));
          p = y;
          y = y % 20;
          System.out.printf("%d nota(s) de R$ 20,00\n", ((p - y)/20));
          p = y;
          y = y % 10;
          System.out.printf("%d nota(s) de R$ 10,00\n", (( p - y)/10));
          p = y;
          y = y % 5;
          System.out.printf("%d nota(s) de R$ 5,00\n", (( p - y)/5));
          p = y;
          y = y % 2;
          System.out.printf("%d nota(s) de R$ 2,00\n", (( p - y)/2));
          p = y;
          y = y % 1;
          System.out.printf("%d nota(s) de R$ 1,00\n", (( p - y)/1));
      }
  }

5.时间转换(https://www.acwing.com/problem/content/656/)

import java.util.Scanner;
public class Main{
    public static void main(String [] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int a = n/3600;
        int b = n%3600/60;
        int c = n%3600%60;
        System.out.printf("%d:%d:%d",a,b,c);
    }
}

6.倍数