【两次过】Lintcode 1204. Keyboard Row

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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.

样例

Input: ["Hello", "Alaska", "Dad", "Peace"]
Output: ["Alaska", "Dad"]

注意事项

You may use one character in the keyboard more than once.
You may assume the input string will only contain letters of alphabet.

---

解题思路：

用HashMap存储键盘，key为字母，value为对应的行号。然后依次判断是否在同一行即可。

public class Solution {
    /**
     * @param words: a list of strings
     * @return: return a list of strings
     */
    public String[] findWords(String[] words) {
        // write your code here
        Map<Character, Integer> map = new HashMap<Character, Integer>();

        initMap(map);
        
        List<String> list = new ArrayList<>();
        
        for(String word : words){
            String temp = word.toLowerCase(); //全部转换为小写字母
            int line = map.get(temp.charAt(0));//首字母所处的行号
            boolean flag = true;
            
            for(int i=1 ; i<temp.length() ; i++){
                if(map.get(temp.charAt(i)) != line){
                    flag = false;
                    break;
                }
            }
            
            if(flag)
                list.add(word);
        }
        
        return list.toArray(new String[0]);
    }
    
    private void initMap(Map<Character, Integer> map){
        map.put('q', 1); 
        map.put('w', 1);
        map.put('e', 1);
        map.put('r', 1);
        map.put('t', 1);
        map.put('y', 1); 
        map.put('u', 1);
        map.put('i', 1);
        map.put('o', 1);
        map.put('p', 1);
        map.put('a', 2);
        map.put('s', 2);
        map.put('d', 2);
        map.put('f', 2);
        map.put('g', 2);
        map.put('h', 2);
        map.put('j', 2);
        map.put('k', 2);
        map.put('l', 2);
        map.put('z', 3);
        map.put('x', 3);
        map.put('c', 3);
        map.put('v', 3);
        map.put('b', 3);
        map.put('n', 3);
        map.put('m', 3);
    }
}