LeetCode-in-Go

392. Is Subsequence

Easy

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

Constraints:

• 0 <= s.length <= 100
• 0 <= t.length <= 104
• s and t consist only of lowercase English letters.

Follow up: Suppose there are lots of incoming s, say s1, s2, ..., sk where k >= 109, and you want to check one by one to see if t has its subsequence. In this scenario, how would you change your code?

Solution

func isSubsequence(s string, t string) bool {
	i := 0
	j := 0
	n := len(t)
	m := len(s)
	if m == 0 {
		return true
	}
	for j < n {
		if s[i] == t[j] {
			i++
			if i == m {
				return true
			}
		}
		j++
	}
	return false
}

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