#392 - Is Subsequence

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Problem Description

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).

Solution

/**
 * @param {string} s
 * @param {string} t
 * @return {boolean}
 */
var isSubsequence = function(s, t) {
  if (s.length > t.length) return false;
  let count = 0;
  for (let i = 0; i < t.length; i++) {
    if (s[count] === t[i]) {
      count++;
    }
  }
  return count === s.length;
};