LC242 Valid Anagram

class Solution:
    def isAnagram(self, s: str, t: str) -> bool: 
        # main idea:  create fixed array to record amount of time each char in s  has appeared
        # time O(N) space O(K) , K = 26 
        if len(s) != len(t):  # optimization1: to exit early 
            return False
        l = [0]*26
        for c in s:
            l[ord(c) - ord('a')] += 1
        for m in t:
            l[ord(m) - ord('a')] -= 1
            if l[ord(m) - ord('a')] < 0:  # optimization2: to exit early 
                return False 
        return not any(l)  # O(N) here