LeetCode题解：Group Anagrams

Given an array of strings, group anagrams together.

For example, given: [“eat”, “tea”, “tan”, “ate”, “nat”, “bat”],
Return:

[
[“ate”, “eat”,”tea”],
[“nat”,”tan”],
[“bat”]
]
Note:
For the return value, each inner list’s elements must follow the lexicographic order.
All inputs will be in lower-case.

题意：找出给定字符串数组中，能组成不同字母顺序的单词的序列，具体看例子

解决思路：符合题意的字符串只要对字母排序，就会呈现一样的顺序，所以我们只要用HashMap存储对应的序列和符合要求的字符串就可以

代码：

public class Solution {
    public List<String> anagrams(String[] strs) {

        Map<String, String> pairs = new HashMap<String, String>();
        List<String> result = new LinkedList<String>();
        Map<String, String> remain = new HashMap<String, String>();

        for (String s:strs) {
            char[] key = s.toCharArray();
            Arrays.sort(key);
            if (key.length == 0) key = null;
            String k = key != null ? new String(key) : null;
            String pair = pairs.put(k, s);
            if (pair != null) {
                result.add(pair);
                remain.put(k, s);
            }
        }

        result.addAll(remain.values());
        return result;
    }
}