思路:以最大堆爲例,建立堆,交換堆頂元素與最後一個爲唄排序元素,直至序列全部有序。
代碼:
#include <iostream>
#include<vector>
using namespace std;
void swap1(vector<int> &a,int i,int j)
{
int temp=a[i];
a[i]=a[j];
a[j]=temp;
}
void adjust(vector<int> &a,int ini_index,int end_index)
{
int left_index=2*ini_index+1;
int right_index=2*ini_index+2;
int max_id=ini_index;
if((left_index<=end_index)&&(a[left_index]>a[max_id]))
max_id=left_index;
if((right_index<=end_index)&&(a[right_index]>a[max_id]))
max_id=right_index;
if(max_id!=ini_index)
{
swap1(a,max_id,ini_index);
adjust(a,max_id,end_index);
}
}
void BuildHeap(vector<int> &a)
{
int length=a.size();
for(int i=length/2-1;i>=0;i--)
{
adjust(a,i,length-1);
}
}
void Heap_sort(vector<int> &a)
{
for(int i=a.size()-1;i>=1;i--)
{
swap1(a,0,i);
adjust(a,0,i-1);
}
}
int main()
{
vector<int> arr{5,3,4,1,8,9,8,6};
BuildHeap(arr);
Heap_sort(arr);
for(auto i:arr)
cout <<i<<' ';
cout<<endl;
return 0;
}
輸出:
1 3 4 5 6 8 8 9
Process returned 0 (0x0) execution time : 0.166 s
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