题解 | #序列和#

import java.util.*;


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) {
        // write code here
        // 15:11
        TreeMap<String,Integer> map = new TreeMap<>();
        for(int i=0;i<strings.length;i++){
            map.put(strings[i],map.getOrDefault(strings[i],0)+1);
        }
        // 排序
        ArrayList<Map.Entry<String,Integer>> list = new ArrayList<>(map.entrySet());
        Collections.sort(list,new Comparator<Map.Entry<String,Integer>>(){
            @Override
            public int compare(Map.Entry<String,Integer> o1,Map.Entry<String,Integer> o2){
                if(o1.getValue().equals(o2.getValue())){
                    return o1.getKey().compareTo(o2.getKey());
                }else{
                    return o2.getValue().compareTo(o1.getValue());
                }
            }
        });

        String[][] res = new String[k][2];

        for(int i=0;i<k;i++){
            res[i][0] = new String(list.get(i).getKey());
            res[i][1] = new String(String.valueOf(list.get(i).getValue()));
        }
        return res;
    }
}

这是借用treeMap的排序做的，不知道算不算？