1347. Minimum Number of Steps to Make Two Strings Anagram

Given two equal-size strings s and t. In one step you can choose any character of t and replace it with another character.

Return the minimum number of steps to make t an anagram of s.

An Anagram of a string is a string that contains the same characters with a different (or the same) ordering.

 

Example 1:

Input: s = "bab", t = "aba"
Output: 1
Explanation: Replace the first 'a' in t with b, t = "bba" which is anagram of s.

Example 2:

Input: s = "leetcode", t = "practice"
Output: 5
Explanation: Replace 'p', 'r', 'a', 'i' and 'c' from t with proper characters to make t anagram of s.

Example 3:

Input: s = "anagram", t = "mangaar"
Output: 0
Explanation: "anagram" and "mangaar" are anagrams.

Example 4:

Input: s = "xxyyzz", t = "xxyyzz"
Output: 0

Example 5:

Input: s = "friend", t = "family"
Output: 4

 

Constraints:

  • 1 <= s.length <= 50000
  • s.length == t.length
  • s and t contain lower-case English letters only.

Rust Solution

struct Solution;

impl Solution {
    fn min_steps(s: String, t: String) -> i32 {
        let mut count: Vec<i32> = vec![0; 26];
        for c in s.chars() {
            let i = (c as u32 - 'a' as u32) as usize;
            count[i] += 1;
        }
        for c in t.chars() {
            let i = (c as u32 - 'a' as u32) as usize;
            count[i] -= 1;
        }
        count.iter().map(|x| x.abs()).sum::<i32>() / 2
    }
}

#[test]
fn test() {
    let s = "bab".to_string();
    let t = "aba".to_string();
    let res = 1;
    assert_eq!(Solution::min_steps(s, t), res);
    let s = "leetcode".to_string();
    let t = "practice".to_string();
    let res = 5;
    assert_eq!(Solution::min_steps(s, t), res);
    let s = "anagram".to_string();
    let t = "mangaar".to_string();
    let res = 0;
    assert_eq!(Solution::min_steps(s, t), res);
    let s = "xxyyzz".to_string();
    let t = "xxyyzz".to_string();
    let res = 0;
    assert_eq!(Solution::min_steps(s, t), res);
    let s = "friend".to_string();
    let t = "family".to_string();
    let res = 4;
    assert_eq!(Solution::min_steps(s, t), res);
}

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