Question
Given an array of strings strs, group the anagrams together. You can return the answer in any order.
An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
https://leetcode.com/problems/group-anagrams/
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| class Solution {
public List<List<String>> groupAnagrams(String[] strs) {
ArrayList<List<String>> res = new ArrayList<List<String>>();
if (strs == null || strs.length == 0) return res;
HashMap<String, List<String>> map = new HashMap<>();
for (int i = 0; i < strs.length; i++) {
char[] curr = strs[i].toCharArray();
Arrays.sort(curr);
String key = String.valueOf(curr);
if (!map.containsKey(key))
map.put(key, new ArrayList<String>());
map.get(key).add(strs[i]);
}
res = new ArrayList<List<String>>(map.values());
return res;
}
}
|
Complexity:
Time complexity: O(n)
Space complexity: O(n)