标签：tar .com 语言 array pre ret start number list
题目描述:输入n个整数，找出其中最小的K个数。例如输入4,5,1,6,2,7,3,8这8个数字，则最小的4个数字是1,2,3,4,。
实现语言：Java
import java.util.ArrayList;
public class Solution {
public ArrayList<Integer> GetLeastNumbers_Solution(int [] input, int k) {
int size=input.length;
ArrayList<Integer> res=new ArrayList<Integer>();
if(size==0||input==null||size<k||k<=0){
return res;
}
int start=0;
int end=size-1;
int index=partition(input,start,end);
while(index!=k-1){
if(index>k-1){
end=index-1;
index=partition(input,start,end);
}else if(index<k-1){
start=index+1;
index=partition(input,start,end);
}
}
for(int i=0;i<k;++i){
res.add(input[i]);
}
return res;
}
private int partition(int[] input,int low,int high){
int pivot=input[low];
while(low<high){
while(low<high&&input[high]>=pivot){
--high;
}
input[low]=input[high];
while(low<high&&input[low]<=pivot){
++low;
}
input[high]=input[low];
}
input[low]=pivot;
return low;
}
}
实现语言：Java
import java.util.ArrayList;
import java.util.PriorityQueue;
import java.util.Comparator;
public class Solution {
public ArrayList<Integer> GetLeastNumbers_Solution(int [] input, int k) {
int size=input.length;
ArrayList<Integer> res=new ArrayList<Integer>();
if(size==0||input==null||size<k||k<=0){
return res;
}
PriorityQueue<Integer> maxHeap=new PriorityQueue<Integer>(k,new Comparator<Integer>(){
@Override
public int compare(Integer o1,Integer o2){
return o2.compareTo(o1);
}
});
for(int i=0;i<size;++i){
if(maxHeap.size()!=k){
maxHeap.offer(input[i]);
}else{
if(maxHeap.peek()>input[i]){
maxHeap.poll();
maxHeap.offer(input[i]);
}
}
}
for(Integer num:maxHeap){
res.add(num);
}
return res;
}
}
标签：tar .com 语言 array pre ret start number list
原文地址：https://www.cnblogs.com/xidian2014/p/10198271.html
