https://leetcode.com/problems/keyboard-row/description/
class Solution {
public:
vector<string> findWords(vector<string>& words) {
set<char> row1 = {'q','w','e','r','t','y','u','i','o','p'};
set<char> row2 = {'a','s','d','f','g','h','j','k','l'};
set<char> row3={'z','x','c','v','b','n','m'};
vector<string> res;
for(auto &elem: words){
bool d1 = true, d2 = true, d3 = true;
for(auto& key:elem){
if(d1){
auto re = row1.find(tolower(key));
if(re == row1.end()) d1 = false;
}
if(d2){
auto re = row2.find(tolower(key));
if(re==row2.end()) d2 = false;
}
if(d3){
auto re = row3.find(tolower(key));
if(re == row3.end()) d3 = false;
}
}
if(d1 || d2 || d3){
res.push_back(elem);
}
}
return res;
}
};