题解 | #最长公共子串#

dp[i] 用来记录i下标是从 dp[i] 到 i 得到的最长字串，最长字串为 dp[i] 到 i 的下标，其实也是滑动窗口的思想

    public String LCS (String str1, String str2) {
        int[] dp = new int[str1.length()+1];
        dp[0] = 0;
        int count = 0;
        int max = 0;
        int[] res = new int[2];
        for(int i = 1; i < dp.length; i++) {
            String tmp = str1.substring(dp[i-1],i);
            if(str2.contains(tmp)) {
                dp[i] = dp[i-1];
                count++;
                if(count > max) {
                    max = count;
                    res[0] = dp[i];
                    res[1] = i;
                }
            }else {
                i = dp[i-1]+1;
                dp[i] = i;
                count = 0;
            }
        }
        return str1.substring(res[0],res[1]);
    }