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: All inputs will be in lower-case.
题意：把应用同样字母的单词，放在一个里面，我这里采用的方法是排序，然后判断是否已经具有了这个主键了，有的话直接放在后面，没有的话，创建一个新的放在后面。
public static List<List<String>> groupAnagrams(String[] strs) {
List<List<String>> list = new ArrayList<>();
HashMap<String, Integer> helper = new HashMap<>();
for (int i = 0; i < strs.length; i++) {
char[] chars = strs[i].toCharArray();
Arrays.sort(chars);
String key = new String(chars);
if (helper.containsKey(key)) {
list.get(helper.get(key)).add(strs[i]);
} else {
List<String> temp = new ArrayList<>();
temp.add(strs[i]);
list.add(temp);
helper.put(key, list.size() - 1);
}
}
return list;
}
