leetcode392. Is Subsequence

题目

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.

思路

将两个字符串顺序比对，跳过t中不匹配的，最后只要判断s是否匹配完就可以了

代码

bool isSubsequence(string s, string t) {        auto i = s.begin();        for(char c : t) {           if(*i == c){               i++;           }        }        return i == s.end();    }