题解 | #查找两个字符串a,b中的最长公共子串#

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
           Scanner in = new Scanner(System.in);
        String a = in.nextLine();
        String b = in.nextLine();
        String shortLine = null;
        String longLine = null;
        if (a.length() < b.length()){
             longLine = b;
             shortLine = a;
        } else {
            longLine = a;
            shortLine = b;
        }
        String comShort[]  = shortLine.split("");
        List<String> list = new ArrayList<>();
        for (int p = 0; p < comShort.length; p++) {
            String tmp = "";
            for (int i = p; i < comShort.length; i++) {
                tmp += comShort[i];
                if (longLine.contains(tmp)) {
                    list.add(tmp);
                }
            }
        }
        int maxlenth = 0;
        for (int i=0;i < list.size();i++) {
            if (list.get(i).length() > maxlenth){
                maxlenth = list.get(i).length();
            }
        }
        int finalMaxlenth = maxlenth;
        String res =  list.stream().filter(s -> s.length()==finalMaxlenth).findFirst().get();
        System.out.println(res);
}
}