Existence of a substring in a string and its reverse

Hash Table String

66.4% acceptance

Feb 25, 2026

111

Given a string s, find any substring of length 2 which is also present in the reverse of s. Return true if such a substring exists, and false otherwise.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn is_substring_present(s: String) -> bool {
    let b = s.as_bytes();
    let rev: Vec<u8> = b.iter().rev().cloned().collect();
    b.windows(2).any(|w| rev.windows(2).any(|r| r == w))
  }
}