堆的STL实现

Posted 2020-12-31 noip

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<vector>
bool cmp(int x,int y)
{
    return x>y;
}
int main()
{
    vector<int> a;
    int num,n;
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&num);
        a.push_back(num);
    }
    make_heap(a.begin(),a.end(),cmp);
    scanf("%d",&num);
    a.push_back(num);
    push_heap(a.begin(),a.end(),cmp);
    cout<<a[0]<<endl;
    pop_heap(a.begin(),a.end(),cmp);
    a.pop_back();
    return 0;
}

pop_heap(a.begin(),a.end(),cmp)  的功能只是将第一个元素放到最后，然后忽略最后一个元素的情况下再维护一遍堆