392 - Is Subsequence

392. Is Subsequence

Problem Statement

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?

Solutions

Rust

impl Solution {
    pub fn is_subsequence(s: String, t: String) -> bool {
        let (mut i, mut j) = (0, 0);

        while i < s.len() && j < t.len() {
            if s.as_bytes()[i] == t.as_bytes()[j] {
                i += 1;
            }
            j += 1;
        }

        i == s.len()
    }
}

...