Leetcode-500. Keyboard Row

前言：为了后续的实习面试，开始疯狂刷题，非常欢迎志同道合的朋友一起交流。因为时间比较紧张，目前的规划是先过一遍，写出能想到的最优算法，第二遍再考虑最优或者较优的方法。如有错误欢迎指正。博主首发CSDN，mcf171专栏。

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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.

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.

这个题目挺简单的，由于很久没做题了，有点手生，花了不少时间。

public class Solution {
    public String[] findWords(String[] words) {
        char[] row1 = new char[]{'q','w','e','r','t','y','u','i','o','p'};
        char[] row2 = new char[]{'a','s','d','f','g','h','j','k','l'};
        char[] row3 = new char[]{'z','x','c','v','b','n','m'};
        List rows = new ArrayList();
        rows.add(row1); rows.add(row2); rows.add(row3);
        List results = new ArrayList();
        for(String item : words){
            for(char[] row : rows){
                int flag = check(item,row);
                if(flag == 1) {results.add(item);break;}
                else if(flag == -1) break;
            }
        }
        return (String[]) (results.toArray(new String[results.size()]));
    }

    private int check(String str, char[] chs){
        str = str.toLowerCase();
        int flag = 0;
        boolean exits = false;
        boolean not_exits = false;
        for(int i = 0; i < str.length(); i++){
            char ch = str.charAt(i);
            if(contains(ch,chs)) exits = true;
            else not_exits = true;
            if(exits && not_exits){flag = -1;break;}

        }
        if(!exits) return 0;
        if(exits && !not_exits) return 1;
        if(flag == -1) return -1;
        return flag;
    }

    private boolean contains(char ch, char[] chs){
        boolean exits = false;
        for(char item : chs){
            if(ch == item) { exits = true; break;}
        }
        return exits;
    }
}