[LeetCode] Keyboard Row 键盘行

class Solution {
public:
    vector<string> findWords(vector<string>& words) {
        vector<string> res;
        unordered_set<char> row1{'q','w','e','r','t','y','u','i','o','p'};
        unordered_set<char> row2{'a','s','d','f','g','h','j','k','l'};
        unordered_set<char> row3{'z','x','c','v','b','n','m'};
        for (string word : words) {
            int one = 0, two = 0, three = 0;
            for (char c : word) {
                if (c < 'a') c += 32;
                if (row1.count(c)) one = 1;
                if (row2.count(c)) two = 1;
                if (row3.count(c)) three = 1;
                if (one + two + three > 1) break;
            }
            if (one + two + three == 1) res.push_back(word);
        }
        return res;
    }
};