字符串：

import java.util.Scanner;
public class Main{
    public static void main(String [] args){
        Scanner input = new Scanner(System.in);
        int n = input.nextInt();
        int m = input.nextInt();
        String[]a = new String[n+1];
        for(int i=1 ;i<=n ;i++){
            a[i] = input.next();        
        }

        for(int i=1 ;i<=m ;i++){
            String temp = a[1];
            for(int j=1 ;j<n ;j++){
                if(a[j].compareTo(a[j+1])>0){  
                    temp = a[j];
                    a[j] = a[j+1];      
                    a[j+1] = temp;
                }
            }
        }
        for(int i=1 ;i<=n ;i++){
            System.out.println(a[i]);
        }
    }
}

英语：

import  java.util.Scanner;

public class Main{

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        String strs[] = str.split(" ");
        StringBuffer restr = new StringBuffer();
        for (int i = strs.length - 1; i >= 0; i--) {

            restr.append(strs[i] + " ");
        }
        System.out.println(restr);
    }
}

IP地址：

import java.util.Scanner;
public class Main{
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String a = input.nextLine();
        int[] b = new int[4];
        int[] c = new int[4];
        for(int i =0;i<4;i++)
        {
            c[i] = Integer.parseInt(a.substring((i+1)*8-8, (i+1)*8));
        }

        for(int i =0;i<4;i++)
        {
            for(int j = 0;j<8;j++)
            {
                b[i]+=Math.pow(2, j)*(c[i]%10);
                c[i] /= 10;
            }
            if(i!=3) {
                System.out.print(b[i]+".");
            } else {
                System.out.print(b[i]);
            }
        }
        input.close();
    }
}

黑洞数

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main{

    private int m = 0;

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        Main ma = new Main();
        ma.m = n;
        ma.getNum(n);
    }

    public void getNum(int n) {
        List list = new ArrayList<>();
        int min = 0 ,max = 0 , count = 0 , position = 0 , temp = n;
        Boolean over = true , flag = true;
        while (over) {
            count = 0;
            temp = n;
            while (flag) {
                temp = temp / 10;
                count++;
                if (temp == 0) {
                    flag = false;
                }
            }
            max = getMax(n, count);
            min = getMin(n, count);
            n = max -min;

            System.out.println(max + "-" + min + "=" + n);

            for(int i=0;i<list.size();i++){
                if(n==(int)list.get(i)){
                    position = i;
                    over = false;
                    break;
                }
            }
            if (over){
                list.add(n);
            }
            flag = true;
        }
        for(int i=position;i<list.size();i++){
            System.out.print(list.get(i)+ " ");
        }
    }

    public int getMax(int n, int count) {
        int[] arr = new int[count];
        for (int m = 0; m < count; m++) {
            arr[m] = n - (n / 10) * 10;
            n = n / 10;
        }
        int c = count;
        int max = 0;
        int j = 0;
        while (c != 0) {
            for (int i = 0; i < c; i++) {
                j = i + 1;
                if (j != c) {
                    if (arr[i] > arr[j]) {
                        int k = arr[i];
                        arr[i] = arr[j];
                        arr[j] = k;
                    }
                }
            }
            c--;
        }
        for (int m = 0; m < count; m++) {
            int p = m;
            while (p != 0) {
                arr[m] = arr[m]*10;
                p--;
            }
            max = max +arr[m];
        }
        return max;
    }

    public int getMin(int n, int count) {
        int[] a = new int[count];
        for (int m = 0; m < count; m++) {
            a[m] = n - (n / 10)*10;
            n = n / 10;
        }
        int c = count;
        int min = 0;
        int j = 0;
        while (c != 0) {
            for (int i = 0; i < c; i++) {
                j = i + 1;
                if (j != c) {
                    if (a[i] < a[j]) {
                        int k = a[i];
                        a[i] = a[j];
                        a[j] = k;
                    }
                }
            }
            c--;
        }
        for (int m = 0; m < count; m++) {
            int p =m;
            while (p != 0) {
                a[m] = a[m]*10;
                p--;
            }
            min = min +a[m];
        }
        return min;
    }
}