题解 | #最长公共子序列(一)#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * s1和s2最长公共子序列的长度
     * @param s1 string字符串 
     * @param s2 string字符串 
     * @return int整型
     */
    public int LCS (String s1, String s2) {
        // write code here
        int mLength = s1.length();
        int nLength = s2.length();
        int[][] dp = new int[mLength + 1][nLength + 1];
        char[] c1 = s1.toCharArray();
        char[] c2 = s2.toCharArray();
        for (int i = 0; i <= mLength; i++) {
            dp[i][0] = 0;
        }
        for (int j = 0; j <= nLength; j++) {
            dp[0][j] = 0;
        }
        for (int i = 1; i <= mLength; i++) {
            for (int j = 1; j <= nLength; j++) {
                if (c1[i - 1] != c2[j - 1]) {
                    dp[i][j] = Math.max(dp[i- 1][j], dp[i][j - 1]);
                } else {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                }
            }
        }
        return dp[mLength][nLength];
    }
}