LeetCode The Hard Way
0200 - 0299

0242 - Valid Anagram (Easy)

https://leetcode.com/problems/valid-anagram/

Problem Statement

Given two strings s and t, return true if t is an anagram of s, and false otherwise.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

Example 1:

Input: s = "anagram", t = "nagaram"
Output: true

Example 2:

Input: s = "rat", t = "car"
Output: false

Constraints:

  • 1 <= s.length, t.length <= 5 * 10^4
  • s and t consist of lowercase English letters.

Follow up: What if the inputs contain Unicode characters? How would you adapt your solution to such a case?

Approach 1: Sort

Written by@wkw
class Solution {
public:
    bool isAnagram(string s, string t) {
        // s and t are anagrams
        // if they are same after being sorted
        sort(begin(s), end(s));
        sort(begin(t), end(t));
        return s == t;
    }
};

Approach 2: Counting

Written by@wkw
class Solution {
public:
    bool isAnagram(string s, string t) {
        // if s and t are anagram,
        // then the frequency of each character would be same
        int cnt[26] = {0};
        for (auto x : s) cnt[x - 'a']++;
        for (auto x : t) cnt[x - 'a']--;
        for (int i = 0; i < 26; i++) {
            if (cnt[i]) {
                return false;
            }
        }
        return true;
    }
};

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