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GroupAnagrams.java
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GroupAnagrams.java
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import java.util.*;
/**
* 49. Group Anagrams 字母异位词分组
* 哈希
* @author LBW
*/
public class GroupAnagrams {
public List<List<String>> groupAnagrams(String[] strs) {
Map<String, List<String>> map = new HashMap<>();
for (String str: strs) {
char[] cs = str.toCharArray();
Arrays.sort(cs);
String key = String.valueOf(cs);
List<String> l = map.getOrDefault(key, new ArrayList<>());
l.add(str);
map.put(key, l);
}
return new ArrayList<>(map.values());
}
public List<List<String>> groupAnagrams2(String[] strs) {
Map<String, List<String>> map = new HashMap<>();
for (String str: strs) {
char[] cs = str.toCharArray();
Arrays.sort(cs);
// 这里不能用 cs.toString() ,否则 key 会无效!
String key = String.valueOf(cs);
if (map.containsKey(key)) {
map.get(key).add(str);
} else {
List<String> l = new ArrayList<>();
l.add(str);
map.put(key, l);
}
}
return new ArrayList<>(map.values());
}
public static void main(String[] args) {
GroupAnagrams groupAnagrams = new GroupAnagrams();
List<List<String>> list = groupAnagrams.groupAnagrams2(new String[]{"eat", "tea", "tan", "ate", "nat", "bat"});
System.out.println(list);
}
}