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by Sumit Chourasia | Oct 03, 2020 | Category :coding | Tags : algorithm binary-search data-structure easy leetcode

Is Subsequence - String - Easy - LeetCode

Is Subsequence - String - Easy - LeetCode

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.

public class Solution {
    public bool IsSubsequence(string s, string t) {
        int i=0;
        int j=0;
        if(s.Length>t.Length){
            IsSubsequence(t,s);
        }
        while(i<s.Length && j<t.Length){
            if(s[i]==t[j]){
                i++;
                j++;
            }
            else{
                j++;
            }
        }
        
        return i==s.Length;
    }
    
    
}

Time Complexity: O(n)

Space Complexity: O(1)

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