500. Keyboard Row

题目描述：题目描述倒是很简单，给出一个键盘，需要我们判断，给出的一个String[]里面的单词中，每一个单词是否都是同一行的。

解题思路：我的解题思路很简单，将每一行作为一个Set，作为一个HashSet，直接使用containsAll的方法，给出结果。

注意：需要注意，进行大写的转换。

public class FindWords {
    public String[] findWords(String[] words) {
        List<String> list = new ArrayList<String>();
        String[] first = {"q" ,"w" ,"e" ,"r" ,"t" ,"y" ,"u" ,"i" ,"o" ,"p"};
        String[] second = {"a" ,"s" ,"d" ,"f" ,"g" ,"h" ,"j" ,"k" ,"l"};
        String[] third = {"z" ,"x" ,"c" ,"v" ,"b" ,"n" ,"m"};
        Set<String> firstSet = new HashSet<String>();
        firstSet.addAll(Arrays.asList(first));
        Set<String> secondSet = new HashSet<String>();
        secondSet.addAll(Arrays.asList(second));
        Set<String> thirdSet = new HashSet<String>();
        thirdSet.addAll(Arrays.asList(third));
        for (String word : words) {
            char[] array = word.toLowerCase().toCharArray();
            List<String> wordList = new ArrayList<String>();
            for(char c : array) {
                wordList.add(String.valueOf(c));
            }
            if(firstSet.containsAll(wordList)) {
                list.add(word);
            }
            else if(secondSet.containsAll(wordList)) {
                list.add(word);
            }
            else if(thirdSet.containsAll(wordList)) {
                list.add(word);
            }
        }
        String[] output = new String[list.size()];
        return list.toArray(output);
    }

    public static void main(String[] args) {
        FindWords findWords = new FindWords();
        String[] input = {"Hello", "Alaska", "Dad", "Peace"};
        String[] output = {"Alaska", "Dad"};

        String[] out = findWords.findWords(input);
        for(String word : out) {
            System.out.println(word);
        }
    }
}