Leetcode题解-500. Keyboard Row

Leetcode题解-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.

American keyboard

Example 1:
Input: [“Hello”, “Alaska”, “Dad”, “Peace”]
Output: [“Alaska”, “Dad”]
Note:

• You may use one character in the keyboard more than once.

• You may assume the input string will only contain letters of alphabet.

思路

把键盘的三行建立三个集合，遍历每个字符串的字符，如果出现在不同的集合里就不符合条件。（这里大写键和Shift不纳入考虑）

代码

小细节：通过set.count()函数来判断字符是否在集合

vector<string> findWords(vector<string>& words) {        vector<string> res;        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'};        for(string s : words){            int first = 0, second = 0, third = 0;            for(char c : s){                if(c < 'a') c+=32;                if(row1.count(c)) first = 1;                if(row2.count(c)) second = 1;                if(row3.count(c)) third = 1;                if(first + second + third > 1) break;            }            if(first + second + third == 1) res.push_back(s);        }        return res;    }