392. Is Subsequence.cpp

#JuneChallenge
/*
Link: https://leetcode.com/problems/is-subsequence/

Given a string s and a string t, check if s is subsequence of t.

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).

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?

Credits:
Special thanks to @pbrother for adding this problem and creating all test cases.

 

Example 1:

Input: s = "abc", t = "ahbgdc"
Output: true
Example 2:

Input: s = "axc", t = "ahbgdc"
Output: false
 

Constraints:

0 <= s.length <= 100
0 <= t.length <= 10^4
Both strings consists only of lowercase characters.
*/

// Solution

class Solution {
public:
    bool isSubsequence(string s, string t) {
        int lenS = s.size(), lenT = t.size(), i;
        int j = 0;
        for(i = 0; i < lenT; i++){
            if (t[i] == s[j])
                j++;
        }
        return j == lenS;
    }
};