[leetcode]500.Keyboard Row Add to List

Given a List of words, return the words that can be typed using letters of alphabet on only one row’s of American keyboard like the image below.

Example 1:

Input: [“Hello”, “Alaska”, “Dad”, “Peace”]Output: [“Alaska”, “Dad”]

Note:

1. You may use one character in the keyboard more than once.
2. You may assume the input string will only contain letters of alphabet.

class Solution {public:    vector<string> findWords(vector<string>& words) {        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'};        vector<unordered_set<char>> rows={row1, row2, row3};        vector<string> ans;        for(int i=0;i<words.size();i++){            int t=0;//先找到第1个字母所在的行            for(int j=0;j<rows.size();j++){                if(rows[j].count((char)tolower(words[i][0])) > 0){                    t=j;                    break;                }            }            bool isOK=true;            for(int j=1;j<words[i].size();j++){                 if(rows[t].find((char)tolower(words[i][j])) ==rows[t].end()){                    isOK=false;                }            }            if(isOK)ans.push_back(words[i]);        }        return ans;    }};