[LeetCode] Keyboard Row 键盘行

旧城等待， 2022-02-01 09:15 193阅读 0赞

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:

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.

这道题给了我们一些单词，问哪些单词可以由键盘上的一行中的键符打出来，难度其实并不大。首先我们把键盘的三行字符分别保存到三个set中，然后遍历每个单词中的每个字符，分别看当前字符是否在三个集合中，如果在，对应的标识变量变为1，我们统计三个标识变量之和就知道有几个集合参与其中了，参见代码如下：

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;
        }
    };

本文转自博客园Grandyang的博客，原文链接：[Keyboard Row 键盘行][Keyboard Row]，如需转载请自行联系原博主。

[American keyboard]: https://leetcode.com/static/images/problemset/keyboard.png
[Keyboard Row]: http://www.cnblogs.com/grandyang/p/6421749.html