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 s = in.next();
        String t = in.next();
        if (t.length() < s.length()) {
            String temp = t;
            t = s;
            s = temp;
        }
        int[][] dp = new int[s.length() + 1][t.length() + 1];
        int max = 0;
        int end = -1;
        for (int i = 1; i <= s.length(); i++) {
            for (int j = 1; j <= t.length(); j++) {
                char cs = s.charAt(i - 1);
                char ct = t.charAt(j - 1);
                if (cs == ct) {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                    if (dp[i][j] > max) {
                        max = dp[i][j];
                        end = i - 1;
                    }
                }
            }
        }
//        if(end==-1){
//            System.out.println("");
//        }else {
//            int begin = end - max + 1;
//            String substring = s.substring(begin, end + 1);
//            System.out.println(substring);
//        }
        int begin = end - max + 1;
        String substring = s.substring(begin, end + 1);
        System.out.println(substring);
    }
}