[leetCode] 392. Is Subsequence (Python)

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:
    def isSubsequence(self, s: str, t: str) -> bool:
        len_s = len(s)
        
        if len_s == 0:
            return True
        
        cnt = 0
        
        for val in t:
            if val == s[cnt]:
                cnt = cnt + 1
                
                if cnt == len_s:
                    return True
                    break
                
        return False

SOMJANG/CODINGTEST_PRACTICE