392 Is Subsequence 1

Joel Castillo Espinosa 2

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).

Examples

  • Example 1:
    • Input: s = “abc”, t = “ahbgdc”
    • Output: true
  • Example 2:
    • Input: s = “axc”, t = “ahbgdc”
    • Output: nums = false

Constraints:

  • 0 ≤ s.length ≤ 100
  • 0 ≤ t.length ≤ $10^{4}$
  • s and t consist only of lowercase English letters.

SOLUTION 3

subseq <- function(s, t){
  # split the string "s"
  s <- strsplit(s, "")
  
  # create pattern (t[1] + ... + t[2] + ... + t[n])
  pattern <- paste(s[[1]], collapse = "([a-z]*)")
  
  # evaluate the pattern
  result <- grepl(pattern, t)
  return(result)
}

Examples using the function

We can use the examples presented before.

subseq("abc","ahbgdc")

## [1] TRUE

subseq(s = "axc", t = "ahbgdc")

## [1] FALSE

  1. This problem is originally from LeetCode, you can find it in Leetcode. ↩

  2. Email: jocastillo@colmex.mx. For more content visit my website: https://joelcastillo.netlify.app
    If you have any questions or suggestions, I’d be grateful to hear from you. ↩

  3. This solution is entirely my own work. It was developed using R version 4.4.1 (2024-06-14 ucrt). ↩