题解 | #字符串出现次数的TopK问题#

每次用java工具时我都感觉相对c来说就像开挂了一样，好不公平。。。：
public class Solution {
/**
* return topK string
* @param strings string字符串一维数组 strings
* @param k int整型 the k
* @return string字符串二维数组
*/
public String[][] topKstrings (String[] strings, int k) {
HashMap<String,Integer> map = new HashMap<>();
TreeSet<string> key = new TreeSet<string>((s1,s2)->map.get(s2)-map.get(s1)==0?s1.compareTo(s2):map.get(s2)-map.get(s1));
for(String s : strings){
map.merge(s, 1, Integer::sum);
}
key.addAll(map.keySet());
String [][] result = new String[k][2];
Iterator<string> iterator = key.iterator();
for(int i = 0;i < k;i++){
String str = iterator.next();
result[i][0] = str;
result[i][1] = String.valueOf(map.get(str));
}
return result;
}
}</string></string></string>