c++学习之--排序5-堆排序

<pre code_snippet_id="76498" snippet_file_name="blog_20131121_1_2374128" name="code" class="cpp"><pre code_snippet_id="76498" snippet_file_name="blog_20131121_1_2374128" name="code" class="cpp">

#include <iostream>

using namespace std;// 58 45 72 86 77 21 34 60void Swap(int *x,int *y){int t;t=*x;*x=*y;*y=t;}void HeapAdjust(int *a,int i,int size){int lchild=2*i;int rchild=2*i+1;int max=i;if(i<=size/2){if(lchild<=size && a[lchild]>a[max]){max=lchild;}if(rchild<=size && a[rchild]>a[max]){max=rchild;}if(max!=i){Swap(&a[i],&a[max]);HeapAdjust(a,max,size);}}}void BuildHeap(int *a,int size){int i;for(i=size/2;i>=1;i--){HeapAdjust(a,i,size);}}void HeapSort(int *a,int size){BuildHeap(a,size);   for(int i=size;i>=1;i--){Swap(&a[1],&a[i]);HeapAdjust(a,1,i-1);}}int main(){int n,i;cin>>n;int *a=new int[n+1];for(i=1;i<=n;i++){cin>>a[i];}HeapSort(a,n);for(i=1;i<=n;i++){cout<<a[i]<<" ";}cout<<endl;return 0;} //堆排序 (大顶堆)//不稳定，建堆需要时间较长 时间复杂度为 O(n*log2(n))