# [Solved] 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).

## Question

Given two strings `s` and `t`, return `true` if `s` is a subsequence of `t`, or `false` otherwise.

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 <= 104`
• `s` and `t` consist only of lowercase English letters.

Follow up: Suppose there are lots of incoming `s`, say `s1, s2, ..., sk` where `k >= 109`, and you want to check one by one to see if `t` has its subsequence. In this scenario, how would you change your code?

## Python Solution

```class Solution:
def isSubsequence(self, s: str, t: str) -> bool:
for i in s:
x = t.find(i)
if x==-1:
return(False)
else:
t=t[x+1:]

return (True)```