LeetCode 1347. Minimum Number of Steps to Make Two Strings Anagram
原题链接在这里:https://leetcode.com/problems/minimum-number-of-steps-to-make-two-strings-anagram/
题目:
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
andt
consist of lowercase English letters only.
题解:
One swap is to make a char c which is not in t become a char in t.
Map to count occurance in s and not in t.
For every extra char, which count is +, it could be used to swap to a char in t but not in s, which is -.
Time Complexity: O(n). n = s.length().
Space: O(1).
AC Java:
1 class Solution { 2 public int minSteps(String s, String t) { 3 int [] map = new int [26]; 4 for(int i = 0; i < s.length(); i++){ 5 map[s.charAt(i) - 'a']++; 6 map[t.charAt(i) - 'a']--; 7 } 8 9 int res = 0; 10 for(int num : map){ 11 if(num > 0){ 12 res += num; 13 } 14 } 15 16 return res; 17 } 18 }