String transforms into another string

Hash Table String Graph Theory

34.6% acceptance

Mar 31, 2026

888

339

Given two strings str1 and str2 of the same length, determine whether you can transform str1 into str2 by doing zero or more conversions. In one conversion you can convert all occurrences of one character in str1 to any other lowercase English character. Return true if and only if you can transform str1 into str2.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn can_convert(str1: String, str2: String) -> bool {
    if str1 == str2 {
      return true;
    }
    let mut mapping = [0u8; 26];
    let mut has_mapping = [false; 26];
    let b1 = str1.as_bytes();
    let b2 = str2.as_bytes();
    for i in 0..b1.len() {
      let c1 = (b1[i] - b'a') as usize;
      let c2 = b2[i] - b'a';
      if has_mapping[c1] {
        if mapping[c1] != c2 {
          return false;
        }
      } else {
        has_mapping[c1] = true;
        mapping[c1] = c2;
      }
    }
    // Need at least one unused char in str2 to use as temp
    let mut used = [false; 26];
    for &b in b2 {
      used[(b - b'a') as usize] = true;
    }
    used.iter().filter(|&&x| x).count() < 26
  }
}