1 #include<stdio.h>
 2 #include<algorithm>
 3 using namespace std;
 4 int partition(int arr[], int s, int e){//返回分裂位置
 5     int x = arr[s];//中轴元素
 6     int j = e+1;
 7     int i = s;
 8     while(i < j){
 9         while(i < e && arr[++i] <= x);
10         while(j > s && arr[--j] > x);
11         if(i >= j) break;
12         swap(arr[j],  arr[i]);
13     }
14     arr[s] = arr[j];
15     arr[j] = x;
16     return j;
17 }
18 int k;
19 void minK(int arr[],int start,int end){
20     if(start >= end) return;
21     int index = partition(arr,start,end);
22     if(index == k) return;
23     //类似二分的思想，比快速排序要少一个递归
24     if(index > k) minK(arr,start,index-1);
25     else minK(arr,index+1,end);
26 }
27 const int M = 200001;
28 int n,arr[M];
29 int main()
30 {
31     while(scanf("%d%d",&n, &k) != EOF){
32         for(int i=0; i<n; i++){
33             scanf("%d", &arr[i]);
34         }
35          --k;
36          minK(arr,0,n-1);
37          sort(arr,arr+k+1);//输出结果需要是排序的
38          for(int i=0; i<k; i++)
39              printf("%d ",arr[i]);
40          printf("%d\n",arr[k]);
41     }
42     return 0;
43 }

 1 #include <algorithm>
 2 #include <cstdio>
 3 using namespace std;
 4 int n,k,a[200000];
 5 void adjustHeap(int idx){
 6     int l = idx*2 + 1;
 7     int r = idx*2 + 2;
 8     int largeIndex = idx;
 9     //先检查边界。k即为要创建的堆的大小
10     while( l<k  || r<k ){
11         if(l<k && a[l] > a[largeIndex]) largeIndex = l;
12         if(r<k && a[r] > a[largeIndex]) largeIndex = r;
13         if(largeIndex != idx){
14             //交换 root和子节点。
15             swap(a[idx], a[largeIndex]);
16             //交换之后继续调整子节点
17             idx = largeIndex;
18             l = idx*2 + 1;
19             r = idx*2 + 2;
20         }else{
21             break; //无需调整
22         }
23     }
24 }
25 void buildHeap(){
26     for(int i= (k-1)/2; i>=0; i--){
27         adjustHeap(i);
28     }
29 }
30 int main(){
31     while(scanf("%d%d", &n, &k) != EOF){
32         for(int i = 0; i < k; i++)
33             scanf("%d", &a[i]);
34         buildHeap();
35         for(int i = k; i < n; i++){
36             scanf("%d", &a[i]);
37             if(a[0] > a[i]){
38                 swap(a[0],a[i]);
39                 adjustHeap(0);
40             }
41         }
42         sort(a,a+k);
43         for(int i = 0; i<k-1; i++)
44                 printf("%d ", a[i]);
45         printf("%d\n", a[k-1]);
46     }
47 }