java实现——030最小的k个数

1.O(nlogk)海量数据

import java.util.TreeSet;

public class T030 {
    public static void main(String[] args){
        int[] data = {4,5,1,6,2,7,3,8};
        TreeSet<Integer> leastNumbers = new TreeSet<Integer>();
        getLeastNumbers(data,leastNumbers,4);
    
    }
    public static void getLeastNumbers(int[] data,TreeSet<Integer> leastNumbers,int k){
        leastNumbers.clear();
        if(k<1||data.length<k)
            return;
        
        for(int i=0;i<data.length;i++){
            if(leastNumbers.size()<k)
                leastNumbers.add(data[i]);
            else{
                System.out.println(leastNumbers.last().hashCode());
                if(data[i]<leastNumbers.last().hashCode()){
                    leastNumbers.remove(leastNumbers.last());
                    leastNumbers.add(data[i]);
                }
            
            }
        }
        System.out.println(leastNumbers.toString());
    }
}