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:
You may use one character in the keyboard more than once.You may assume the input string will only contain letters of alphabet.
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判斷一個單詞的字母是否都在鍵盤的同一行。
代碼：
class Solution{public:	vector<string> findWords(vector<string>& words) 	{		s = "QWERTYUIOP";		make_map(1);		s = "ASDFGHJKL";		make_map(2);		s = "ZXCVBNM";		make_map(3);		vector<string>res;		for(auto word:words)		{			int n = 0;			for(auto c:word)			{				int k = toupper(c) - 'A';				if(n != 0 && n != map[k]) 				{					n = 4;					break;				}				n = map[k];			}			if(n < 4) res.push_back(word);		}		return res;	}PRivate:	int map[26];	string s;	void make_map(int n)	{		for(auto c:s)		{			map[c-'A'] = n;		}	}};