Is Subsequence

📜 Problem Statement: 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).

Examples

🔹 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?