最大堆

typedef struct heapstruct *maxheap;
struct heapstruct{
    int *elements;/* 存储堆元素的数组 */
    int size;/* 堆的当前元素个数 */
    int capacity;/* 堆的最大容量 */
};

maxheap create(int maxsize){
    /* 创建容量为maxsize的空的最大堆 */
    maxheap h = malloc(sizeof(struct heapstruct));
    h->elements = malloc((maxsize+1) * sizeof(int)); 
    h->size = 0;
    h->capacity = maxsize;
    h->elements[0] = maxdata;
    /* 定义“哨兵”为大于堆中所有可能元素的值，便于以后更快操作 */
    return h;
}

void insert(maxheap h,int item){
    int i;
    if(isfull(h)){
        cout<<"堆满了"<<endl;
        return;
    }
    i = ++h->size;
    for(; h->elements[i/2] < item; i/=2){
        h->elements[i] = h->elements[i/2];
    }
    h->elements[i] = item;
}

int deletemax(maxheap h){
    int parent,child;
    int maxitem,temp;
    if(isempty(h)){
        cout<<"最大堆空"<<endl;
        return;
    }
    maxitem = h->elements[1];
    temp = h->elements[h->size--];
    for(parent = 1; parent*2 <= h->size; parent = child){
        child = parent * 2;
        if((child != h->size)&&
           (h->elements[child] < h->elements[child+1]))
            child++;
        if(temp >= h->elements[child])break;
        else
            h->elements[parent] = h->elements[child];
    }
    h->elements[parent] = temp;
    return maxitem;
}

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 1e7 + 5;
int n, m, k, sum, a[maxn];
string s;
queue<int> q;

void up(int p){
    while(p > 1 && a[p] > a[p / 2]){
        swap(a[p], a[p / 2]);
        p = p / 2;
    }
}

void down(int p){
    while(p * 2 <= n){
        int u = p * 2;
        if(u + 1 <= n && a[u + 1] > a[u]){
            u++;
        }
        if(a[u] > a[p]){
            swap(a[u], a[p]);
            p = u;
        }
        else break;
    }
}

void makeheap(){
    for(int i = n / 2; i >= 1; i--){
        down(i);
    }
}

void push(int x){
    a[++n] = x;
    up(n);
}

int top(){
    return a[1];
}

void pop(){
    swap(a[1], a[n--]);
    down(1);
}

int main(){
    //ios_base::sync_with_stdio(0);
    //cin.tie(); cout.tie();
    n = 10;
    for(int i = 1; i <= n; i++)
        a[i] = i;
    makeheap();
    for(int i = 1; i <= 10; i++){
        push(i + 10);
    }
    while(n > 0){
        cout<<top()<<endl;
        pop();
    }
    return 0;
}