LeetCode部分题解

LeetCode Algorithm部分.392

【392】 Is Subsequence

Given a string s and a string t, check if s is subsequence of t.
You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (<=100).
A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relative positions of the remaining characters. (ie, “ace” is a subsequence of “abcde” while “aec” is not).
Example 1:
s = “abc”, t = “ahbgdc”
Return true.
Example 2:
s = “axc”, t = “ahbgdc”
Return false.
Follow up:
If there are lots of incoming S, say S1, S2, … , Sk where k >= 1B, and you want to check one by one to see if T has its subsequence. In this scenario, how would you change your code?

此题大意为在长的字符串中查找一个短的字符串是否存在。下面是我的实现

  bool isSubsequence(string s, string t) {
        int j = 0;
        for(int i = 0; i < t.size(); i++){
            if(j == s.size()) break;
            if(s[j]==t[i]) j++;
        }
        return j == s.size();
    }