Valid Anagram

Two strings are anagrams when they contain the exact same letters with the exact same frequencies, possibly rearranged. "listen" and "silent" are anagrams; "hello" and "world" are not. This is the gateway problem for hash-map frequency counting and one of the most common warm-up questions in a phone screen.

Valid Anagram

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

Examples

Example 1:

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

Example 2:

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

Example 3:

• Input: s = "", t = ""
• Output: true

Constraints

• 0 <= s.length, t.length <= 5 * 10^4
• s and t consist of lowercase ASCII letters only.

Follow-up

What if the inputs contained Unicode characters? Does your O(1)-extra-space-with-fixed-alphabet approach still hold up, or do you need to fall back to a hash map?