**Subsequence Strings - Amazon Top Interview Questions**

### Problem Statement :

Given two lowercase alphabet strings s1 and s2, determine if s1 is a subsequence of s2. Constraints n ≤ 100,000 where n is the length of s1 m ≤ 100,000 where m is the length of s2 Example 1 Input s1 = "ppl" s2 = "apple" Output True Example 2 Input s1 = "ale" s2 = "apple" Output True Example 3 Input s1 = "elppa" s2 = "apple" Output False

### Solution :

` ````
Solution in C++ :
bool solve(string s1, string s2) {
int j = 0;
for (int i = 0; i < s2.length() && j < s1.length(); i++) {
if (s1[j] == s2[i]) j++;
}
return (j == (int)s1.length());
}
```

` ````
Solution in Python :
class Solution:
def solve(self, s1, s2):
n = len(s1)
m = len(s2)
s1_ptr = 0
s2_ptr = 0
while s1_ptr < n and s2_ptr < m:
if s1[s1_ptr] == s2[s2_ptr]:
s1_ptr += 1
s2_ptr += 1
return s1_ptr == n
```

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