1347. Minimum Number of Steps to Make Two Strings Anagram

Problem

You are given two strings of the same length 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. 

  Constraints:

• 1 <= s.length <= 5 * 104

• s.length == t.length

• s and t consist of lowercase English letters only.

Solution

/**
 * @param {string} s
 * @param {string} t
 * @return {number}
 */
var minSteps = function(s, t) {
    var map = Array(26).fill(0);
    var a = 'a'.charCodeAt(0);
    for (var i = 0; i < t.length; i++) {
        map[t.charCodeAt(i) - a]++;
    }
    for (var j = 0; j < s.length; j++) {
        map[s.charCodeAt(j) - a]--;
    }
    var res = 0;
    for (var k = 0; k < 26; k++) {
        res += Math.abs(map[k]);
    }
    return res / 2;
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(1).