Top K Frequent Elements

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题目链接

import java.util.Arrays;import java.util.LinkedList;import java.util.List;import java.util.PriorityQueue;public class Solution {    public static void main(String args[])    {        Solution obj=new Solution();        List<Integer> result=obj.topKFrequent(new int[]{1,1,1,2,2,3},2);        for (Integer integer : result) {            System.out.println(integer);        }    }    public List<Integer> topKFrequent(int[] nums, int k) {        Arrays.sort(nums);        PriorityQueue<Record> heap=new PriorityQueue<Record>();        int last=nums[0];        int count=0;        for(int i=0;i<nums.length;i++)        {            if(last!=nums[i])            {                heap.add(new Record(last, count));                count=1;                last=nums[i];            }            else            {                count++;            }        }        heap.add(new Record(last, count));        List<Integer> result=new LinkedList<Integer>();        for(int i=0;i<k;i++)        {            result.add(heap.poll().nums);        }        return result;    }}class Record implements Comparable<Record>{    int nums;    int count;    Record(int nums,int count)    {        this.nums=nums;        this.count=count;    }    @Override    public int compareTo(Record o) {        return count<o.count?1:-1;    }}

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