Question

link

Stats

Ratings/Color = 1(white) 2(lime) 3(yellow) 4/5(red)

Analysis

This is not an extremely difficult question, but I always get TLE error (Time limit exceeded), before I realize that I have to use HashMap.

Solution

The solution is making use of HashMap and sorting to check anagrams. For more, read this blog.

My code

public class Solution {
    public List<String> anagrams(String[] strs) {
        List<String> ans = new ArrayList<String>();
        if (strs == null || strs.length == 0) {
            return ans;
        }
        HashMap<String, List<String>> map = new HashMap<String, List<String>>();
        for (String str: strs) {
            char[] chars = str.toCharArray();
            Arrays.sort(chars);
            String sorted = String.valueOf(chars);
            if (!map.containsKey(sorted)) {
                map.put(sorted, new ArrayList<String>());
            }
            map.get(sorted).add(str);
        }
        for (List<String> list: map.values()) {
            if (list.size() > 1) {
                ans.addAll(list);
            }
        }
        return ans;
    }
}