:orphan:

Valid Anagram
=============

.. highlight:: none

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:**

.. container:: example-block

   **Input:** s = "anagram", t = "nagaram"

   **Output:** true

**Example 2:**

.. container:: example-block

   **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?

.. highlight:: python

Pattern
-------
Hash Table, String, Sorting

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.

Code
----

.. literalinclude:: ../problems/easy/valid-anagram/valid_anagram__approach_1.py
    :language: python
    :lines: 10-

Test
----
>>> from valid_anagram__approach_1 import isAnagram
>>> isAnagram('anagram', 'nagaram')
True
>>> isAnagram('rat', 'car')
False

Complexity
----------
| :math:`n` is the length of ``s`` and ``t``.
| Time: :math:`O(n)` — count characters in ``s`` and ``t``
| Auxiliary Space: :math:`O(1)` — dictionary size bounded by character set (26 lowercase letters)

.. autofunction:: valid_anagram__approach_1.isAnagram