242. 有效的字母异位词

class Solution {
public:
    bool isAnagram(string s, string t) 
    {
        if (s.length() != t.length()) {
            return false;
        }
        vector<int> table(26, 0);
        for (auto ch: s) {
            table[ch - 'a']++;
        }
        for (auto ch: t) {
            table[ch - 'a']--;
            if (table[ch - 'a'] < 0) {
                return false;
            }
        }
        return true;
    }
};