题目描述：给定一个字符串数组，将字母异位词组合在一起。字母异位词指字母相同，但排列不同的字符串。
示例：输入: ["eat", "tea", "tan", "ate", "nat", "bat"],
输出:
[
["ate","eat","tea"],
["nat","tan"],
["bat"]
]
Java代码：
class Solution {
public List<List<String>> groupAnagrams(String[] strs) {
if(strs.length == 0) return new ArrayList();
Map<String,List> ans = new HashMap<String,List>();
int[] count = new int[26];
for(String s:strs) {
Arrays.fill(count,0);
for(char c:s.toCharArray()) count[c-'a']++;
StringBuilder sb = new StringBuilder("");
for(int i=0;i<26;i++) {
sb.append('#');
sb.append(count[i]);
}
String key = sb.toString();
if(!ans.containsKey(key)) ans.put(key,new ArrayList());
ans.get(key).add(s);
}
return new ArrayList(ans.values());
}
}
