392-is-subsequence

392. Is Subsequence (Easy) (https://leetcode.com/problems/is-subsequence/)

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). Constraints: - 0 <= s.length <= 100 - 0 <= t.length <= 10^4 - s and t consist only of lowercase English letters.

function isSubsequence(s: string, t: string): boolean {
  let sIdx = 0
  for (let i = 0; i < t.length && sIdx < s.length; i++) {
    // без аллокации
    if (t.charCodeAt(i) === s.charCodeAt(sIdx)) {
      sIdx++
    }
  }
 
  return sIdx === s.length
}
 
// Local check:
console.log(isSubsequence("abc", "ahbgdc"))
console.log(isSubsequence("axc", "ahbgdc"))

Example 1:
    Input: s = "abc", t = "ahbgdc"
    Output: true
 
  Example 2:
    Input: s = "axc", t = "ahbgdc"
    Output: false

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