Day 7 - Valid Anagram

🧩 Problem:

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

📏 Constraints:

• 1 <= s.length, t.length <= 5 * 10^4

• s and t consist of lowercase English letters

🧠 How to Approach It

An anagram means both strings contain the same characters, just in a different order. The key insight is:

• Same characters

• Same frequencies

There are several ways to solve this:

• ✅ Hash maps / dictionaries to count character frequency

• 🧵 Or sort both strings and compare (less efficient for large inputs)

Here we use two dictionaries and compare their contents.

✅ Python Solution:

class Solution:
    def isAnagram(self, s: str, t: str) -> bool:
        if len(s) != len(t):
            return False

        s_count = {}
        t_count = {}

        for i in s:
            s_count[i] = s_count.get(i, 0) + 1
        
        for i in t:
            t_count[i] = t_count.get(i, 0) + 1
        
        return s_count == t_count

💡 Optional Unicode support:

from collections import Counter

def isAnagram(s: str, t: str) -> bool:
    return Counter(s) == Counter(t)

🧵 TL;DR:

• Count characters using dictionaries or Counter

• Equal counts = valid anagram

• Works in O(n) time