还没有吃透
#include<bits/stdc++.h>
using namespace std;
const int N = 100100;
int hp[N],h[N],ph[N],sizes;
void heap_swap(int a,int b)
{
swap(ph[hp[a]],ph[hp[b]]);
swap(hp[a],hp[b]);
swap(h[a],h[b]);
}
void down(int u)
{
int t = u;
if(u*2 <= sizes&& h[u*2]<h[t]) t = u * 2; //如果左儿子存在并且比父节点小则交换下标
if(u*2+1<= sizes&& h[u*2+1]<h[t]) t = 2 * u + 1; //同上 右儿子
if(u != t)
{
heap_swap(u ,t);
down(t);
}
}
void up(int u)
{
while(u / 2 && h[u/2]>h[u]) //父节点存在,并且父节点的值大于u
{
heap_swap(u/2 , u);
u/=2;
}
}
int main()
{
int n,m=0;;
scanf("%d",&n);
while(n--)
{
char op[10];
int k,x;
scanf("%s",op);
if(!strcmp(op,"I"))
{
scanf("%d",&x);
sizes++;
m++;
ph[m] = sizes,hp[sizes] = m;
h[sizes] = x;
up(sizes);
}
else if(!strcmp(op,"PM")) printf("%d\n",h[1]);
else if(!strcmp(op,"DM"))
{
heap_swap(1,sizes);
sizes--;
down(1);
}
else if(!strcmp(op,"D"))
{
scanf("%d",&k);
k = ph[k];
heap_swap(k,sizes);
sizes--;
down(k),up(k);
}
else{
scanf("%d%d",&k,&x);
k = ph[k];
h[k] = x;
down(k),up(k);
}
}
}