500. Keyboard Row

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.

image

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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.

方法一:

https://discuss.leetcode.com/topic/77761/c-solution

C++ solution

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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> validWords;
for(int i=0; i<words.size(); ++i){
int row=0;

for(int k=0; k<3; ++k){
if(rows[k].count((char)tolower(words[i][0])) > 0) row = k;
}

validWords.push_back(words[i]);
for(int j=1; j<words[i].size(); ++j){
if(rows[row].count((char)tolower(words[i][j])) == 0){
validWords.pop_back();
break;
}
}

}
return validWords;
}
};

我的代码实现:

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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'};
vector<unordered_set<char>> rows{row1, row2, row3};

for(int i=0; i<words.size(); i++){
int row;
for(int j=0; j<3; j++){
if(rows[j].count(tolower(words[i][0]))>0){
row = j;
break;
}
}
res.push_back(words[i]);
for(int k=0; k<words[i].size(); k++){
if(rows[row].count(tolower(words[i][k]))==0){
res.pop_back();
break;
}
}
}
return res;
}
};
谢谢你,可爱的朋友。