Valid Anagram

class Solution {
public:
    bool isAnagram(string s, string t) {
        unordered_map<char, int> hashTable;
        for(int i=0; i<s.size(); ++i)
            hashTable[s[i]] += 1;
        
        for(int i=0; i<t.size(); ++i)
        {
            if(hashTable.find(t[i]) != hashTable.end() && hashTable[t[i]] > 0)
                hashTable[t[i]] -= 1;
            else
                return false;
        }
        
        unordered_map<char, int>::iterator iter;
        for(iter = hashTable.begin(); iter != hashTable.end(); ++iter)
            if(iter->second > 0)
                return false;
        
        return true;
    }
};