leetcode 392. is subsequence

Description：

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.

Solution:

水题了，判断子序列，还是用两个指针的办法来解决。

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class  
{
public:
    bool isSubsequence(string s, string t) 
    {
        int lens = s.size();
        int lent = t.size();
        
        int s_index = 0, j = 0;
        for ( ; s_index < lens && j < lent; ++j)
        {
            if (t[j] == s[s_index])
                ++s_index;
        }
        return s_index == lens;
    }
};