_49.java

package com.fishercoder.solutions;

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

/**
 * 49. Group Anagrams
 *
 * 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.
 */

public class _49 {

  public static class Solution1 {
    public List<List<String>> groupAnagrams(String[] strs) {
      Map<String, List<String>> map = new HashMap<>();
      for (String word : strs) {
        char[] c = word.toCharArray();
        Arrays.sort(c);
        String key = new String(c);
        if (!map.containsKey(key)) {
          map.put(key, new ArrayList<>());
        }
        map.get(key).add(word);
      }
      return new ArrayList<>(map.values());
    }
  }
}