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Is Subsequence

URL: https://leetcode.com/problems/is-subsequence/description/

Description:

Given two strings s and t, return true if s is a subsequence of t, or false otherwise. A subsequence of a string is a new string that is formed from the original string by deleting some (can be none) of the characters without disturbing the relative positions of the remaining characters. (i.e., "ace" is a subsequence of "abcde" while "aec" is not).

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
s and t consist only of lowercase English letters.

Follow up: Suppose there are lots of incoming s, say s1, s2, ..., sk where k

= 10^9, and you want to check one by one to see if t has its subsequence. In this scenario, how would you change your code?

Solution Code:

class Solution:
    def isSubsequence(self, s: str, t: str) -> bool:

        found = 0
        x = 0
        for i in s:
            while x < len(t) and t[x] != i:
                x += 1
            if x < len(t):
                x += 1
                found += 1
            else:
                break

        return found == len(s)