Check if one string swap can make strings equal

Hash Table String Counting

49.5% acceptance

Feb 25, 2026

1705

You are given two strings s1 and s2. Return true if it is possible to make both strings equal by performing at most one string swap on exactly one of the strings.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn are_almost_equal(s1: String, s2: String) -> bool {
    let diffs: Vec<usize> = s1.bytes().zip(s2.bytes())
      .enumerate()
      .filter(|&(_, (a, b))| a != b)
      .map(|(i, _)| i)
      .collect();
    match diffs.len() {
      0 => true,
      2 => {
        let (i, j) = (diffs[0], diffs[1]);
        let b1 = s1.as_bytes();
        let b2 = s2.as_bytes();
        b1[i] == b2[j] && b1[j] == b2[i]
      }
      _ => false,
    }
  }
}