ValidAnagram

Problem

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

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

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`
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?

Solution

For two strings to be anagrams, they must have the same number of each character. We can track the occurrences of each character in a dictionary, incrementing for s and decrementing for t. If the dictionary only contanins 0’s, then s and t are anagrams.

Pattern

Hash Table, String, Sorting

Code

def isAnagram(s: str, t: str) -> bool:
    """Checks if ``s`` and ``t`` are anagrams of each other.
    """
    d = {}
    for char in s:
        if char in d:
            d[char] += 1
        else:
            d[char] = 1
    for char in t:
        if char in d:
            d[char] -= 1
        else:
            return False
    return all(count == 0 for char, count in d.items())

Test

>>> from ValidAnagram import isAnagram
>>> isAnagram('anagram', 'nagaram')
True
>>> isAnagram('rat', 'car')
False

ValidAnagram.isAnagram(s: str, t: str) → bool: Checks if s and t are anagrams of each other.