# Leetcode Is Subsequence problem solution

In this Leetcode Is Subsequence problem solution you have 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).

## Problem solution in Python.

```class Solution:
def isSubsequence(self, s: str, t: str) -> bool:
j,n=0,len(t)
for i in s:
while j<n and t[j]!=i:
j+=1
if j>=n:
return False
j+=1
return True
```

## Problem solution in Java.

```public boolean isSubsequence_basic(String s, String t) {
if(s==null) return false;
if(s.length()==0) return true;
int i=0, j=0;
while(i<s.length() && j<t.length()){
char cs = s.charAt(i);
char ct = t.charAt(j);
if(cs==ct){
i++;
}
j++;
}
return i==s.length();
}
```

## Problem solution in C++.

```class Solution {
public:
bool isSubsequence(string s, string t) {
int sI = 0;
if(s.length() == 0) return true;
for(int i = 0 ; i < t.length();i++){
if(t[i] == s[sI]){
++sI;
}
if(sI == s.length()) return true;
}
return false;
}
};
```

## Problem solution in C.

```bool isSubsequence(char * s, char * t){
int j = 0;

for (int i = 0; s[j] && t[i]; i++) {
if (t[i] == s[j]) {
j += 1;
}
}

return (j == strlen(s));
}
```

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