LeetCode

题目：

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.

思路：

HashMap, 对每个字符串所包含的字符进行排序，得到一个key，value为响应的list。

package anagram;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;

public class GroupAnagrams {

    public List<List<String>> groupAnagrams(String[] strs) {
        HashMap<String, List<String>> map = new HashMap<String, List<String>>();
        for (int i = 0; i < strs.length; ++i) {
            char[] chars = strs[i].toCharArray();
            Arrays.sort(chars);
            String key = String.valueOf(chars);
            if (map.containsKey(key)) {
                map.get(key).add(strs[i]);
            } else {
                List<String> list = new ArrayList<String>();
                list.add(strs[i]);
                map.put(key, list);
            }
        }
        List<List<String>> res = new ArrayList<List<String>>();
        for (List<String> l : map.values()) {
            Collections.sort(l);
            res.add(l);
        }
        
        return res;
    }
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String[] strs = { "eat", "tea", "tan", "ate", "nat", "bat" };
        GroupAnagrams g = new GroupAnagrams();
        List<List<String>> res = g.groupAnagrams(strs);
        for (List<String> subRes : res) {
            for (String s : subRes)
                System.out.print(s + "	");
            System.out.println("
");
        }
    }

}

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:

1. For the return value, each inner list's elements must follow the lexicographic order.
2. All inputs will be in lower-case.