题解 | #查找两个字符串a,b中的最长公共子串#

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s1 = in.next();
        String s2 = in.next();
        boolean flag = s1.length()<=s2.length();
        String str1;
        String str2;
        //确保str1为短的那一个字符串
        if(flag){
            str1 = s1;
            str2 = s2;
        }else{
            str1 = s2;
            str2 = s1;
        }
        //在str1中从最长的字串开始遍历，看str2中是否包含，若包含则打印，结束循环
        outer:
        for(int i = str1.length(); i>0; i--){
            for(int j = 0; j<str1.length(); j++){
                if(j+i<=str1.length()){
                    if(str2.contains(str1.substring(j,j+i))){
                        System.out.print(str1.substring(j,j+i));
                        break outer;
                    }
                }
            }
        }
    }
}