Ifihan/main.md

## main.md

      
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    Is Subsequence

Question on Leetcode - Easy
Approach

The approach taken was to use a pointer intialized at 0, for the sequence s string. This pointer servers as a counter which the increases for every positive match against the main string.
Afterwards, I traversed through the main string t and returned the a boolean of if the pointer value was the same as the length of the sequence s.
Code

class Solution:
    def isSubsequence(self, s: str, t: str) -> bool:
        seqid = 0
        for value in t:
            if seqid == len(s):
                return True
            if s[seqid] == value:
                seqid += 1
        return seqid == len(s)
Complexities


Time Complexity: O(n) for the length of the main string.
Space complexity: O(1) constant space as nothig is really added apart from the pointer.