242. Valid Anagram

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<sup>4</sup>

• s and t consist of lowercase English letters.

Solution:

class Solution:
    def isAnagram(self, s: str, t: str) -> bool:
        # solution 1
        # return sorted(s) == sorted(t)

        # solution 2
        # return Counter(s) == Counter(t)

        # solution 3
        if len(s) != len(t):
            return False

        countS, countT = {}, {}

        for i in range(len(s)):
            countS[s[i]] = 1 + countS.get(s[i],0)
            countT[t[i]] = 1 + countT.get(t[i],0)

        for c in countS:
            if countS[c] != countT.get(c,0):
                return False

        return True