• 堆的屬性

1. 完全二叉樹
2. 每個節點的值都大于（最大堆）或都小于（最小堆）子節點的值

堆只是一種數據的組織形式，存儲結構可以用數組，在構建堆的過程中，可以使用完全二叉樹的性質求父子節點的下標。

父節點的下標 = 向下取整 ( (子節點下標 - 1) /  2)

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
void minheap();
void maxheap();
using namespace std;
int arr[8] = { 53,17,78,9,45,65,87,23 };
int *a = new int[8];//保存小根堆
int index = 0;
int main()
{minheap();cout << "建立的最小堆為：" << endl;for (int i = 0; i < 8; i++){cout << a[i] <<" ";}system("pause");
}void maxheap() {while(index < 8) {a[index] = arr[index];if (index != 0) {int son_index = index;int par_index = floor((son_index - 1) / 2);while(a[par_index] < a[son_index]) {int tmp = a[par_index];a[par_index] = a[son_index];a[son_index] = tmp;son_index = par_index;par_index = floor((par_index - 1) / 2);}}index ++;}
}
void minheap()
{while (index < 8) {a[index] = arr[index];if (index != 0) {int son_index = index;int par_index = floor((son_index - 1) / 2);while (a[par_index] > a[son_index]) {//小根堆:父節點大的話需要交換int temp = a[par_index];//交換a[par_index] = a[son_index];a[son_index] = temp;son_index = par_index;//迭代看之前的是否需要調整par_index = floor((son_index - 1) / 2);}}index ++;}
}