IsSubsequence.java

/*
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).

Example 1:
  Input: s = "abc", t = "ahbgdc"
  Output: true

Example 2:
  Input: s = "axc", t = "ahbgdc"
  Output: false

Link: [https://leetcode.com/problems/is-subsequence/description/]
*/

class Solution {
    public boolean isSubsequence(String s, String t) {
        int indexInS = 0;
        int indexInT = 0;

        while( indexInS < s.length() && indexInT < t.length() ){
            char charInS = s.charAt(indexInS);
            char charInT = t.charAt(indexInT);
            if(charInS == charInT){
                indexInS++;
                indexInT++;
            } else{
                indexInT++;
            }
        } 

        return indexInS == s.length();
    }
}