[LeetCode] Keyboard Row 鍵盤行

 

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.

 

這道題給了我們一些單詞，問哪些單詞可以由鍵盤上的一行中的鍵符打出來，難度其實並不大。首先我們把鍵盤的三行字符分別保存到三個set中，然后遍歷每個單詞中的每個字符，分別看當前字符是否在三個集合中，如果在，對應的標識變量變為1，我們統計三個標識變量之和就知道有幾個集合參與其中了，參見代碼如下：

 

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;
    }
};

 

參考資料：

https://discuss.leetcode.com/topic/77754/java-1-line-solution-via-regex-and-stream

 

LeetCode All in One 題目講解匯總(持續更新中...)