Valid Anagram

Given two strings s and t, write a function to determine if t is an anagram of s.

For example, s = "anagram", t = "nagaram", return true. s = "rat", t = "car", return false.

Note: You may assume the string contains only lowercase alphabets.

Follow up: What if the inputs contain unicode characters? How would you adapt your solution to such case?

Solution: Using hash table

bool isAnagram(string s, string t) {
    if (s.length() != t.length()) return false;

    unordered_map<char, int> table;
    int count = 0;
    for (auto ch: s) {
        table[ch] += 1;
        count += 1;
    }

    for (auto ch: t) {
        if (table.find(ch) != table.end() && table[ch] > 0) {
            table[ch] -= 1; 
            count -= 1;
        }
    }

    return count == 0;
}

Solution: Using array

    bool isAnagram(string a, string b) {
        if (a.size() != b.size()) return false;

        int arr[256] = {0};
        for (int i=0; i<a.size(); i++) {
            arr[a[i]]++;
            arr[b[i]]--;
        }

        for (int i=0; i<256; i++) {
            if (arr[i] != 0) return false;
        }
        return true;
    }