LeetCode 1347 Minimum Number of Steps to Make Two Strings Anagram

LeetCode

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*sandt` consist of lowercase English letters only.

题目大意：

通过替换字母使得两字符为同位词Anagram

解题思路：

统计某一个词的词频，遍历另一个单词，减去词频，若不够减(小于0)，就加步数

解题步骤：

N/A

注意事项：

Python代码：

def minSteps(self, s: str, t: str) -> int:
	char_to_count_t = collections.Counter(t)
	steps = 0
	for char in s:
		if char in char_to_count_t and char_to_count_t[char] > 0:
			char_to_count_t[char] -= 1
		else:
			steps += 1
	return steps

算法分析：

时间复杂度为O(n)，空间复杂度O(n)