题解 | #最长公共子串#

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
     *
     * longest common substring
     * @param str1 string字符串 the string
     * @param str2 string字符串 the string
     * @return string字符串
     */
    public String LCS (String str1, String str2) {
        // write code here
        int maxLen = 0;
        int str1Index = 0;

        int[][] dp = new int[str1.length()+1][str2.length()+1];
        for(int i=1;i<dp.length;i++){
            for(int j=1;j<dp[0].length;j++){
                if(str1.charAt(i-1)== str2.charAt(j-1)){
                    dp[i][j] = dp[i-1][j-1]+1;
                    if(maxLen < dp[i][j]){
                        maxLen = dp[i][j];
                        str1Index = i;
                    }
                }
            }
        }
        return str1.substring(str1Index - maxLen,str1Index);
    }


}