题解 | #最长公共子序列(二)#

import java.util.*;


public class Solution {
    /**
     * longest common subsequence
     * @param s1 string字符串 the string
     * @param s2 string字符串 the string
     * @return string字符串
     */
    public static String LCS(String s1, String s2) {
        int m = s1.length();
        int n = s2.length();
        //int[][] dp = new int[m+1][n+1];
        String[][] s = new String[m + 1][n + 1];
        for (int i = 0; i <= n; i++) {
            s[0][i] = " ";
        }
        for (int i = 0; i <= m; i++) {
            s[i][0] = " ";
        }
        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                if (s1.charAt(i - 1) == s2.charAt(j - 1)) {
                    //dp[i][j] = dp[i - 1][j - 1] + 1;
                    s[i][j] = s[i - 1][j - 1].concat(String.valueOf(s1.charAt(i - 1)));
                } else {
                    //dp[i][j] = Math.max(dp[i - 1][j],dp[i][j - 1]);
                    s[i][j] = s[i - 1][j].length() > s[i][j - 1].length() ? s[i - 1][j] : s[i][j -
                              1];
                }
            }
        }
        if (s[m][n].equals(" "))
            return "-1";
        return s[m][n].trim();
    }
}

基本上和一差不多