题目描述

输入样例

8
I -10
PM
I -10
D 1
C 2 8
I 6
PM
DM

输出样例

-10
6

参考代码

#include <iostream>
using namespace std;const int N = 1e5 + 10;
int h[N], hp[N], ph[N];
int n, m;// 堆内交换操作传入的是堆中的下标
void heap_swap(int a, int b)
{swap(ph[hp[a]], ph[hp[b]]); // 这个才是核心swap(hp[a], hp[b]); // 这个是辅助swap(h[a], h[b]);
}void down(int u)
{int t = u;if (u * 2 <= n && h[t] > h[u * 2]) t = u * 2;if (u * 2 + 1 <= n && h[t] > h[u * 2 + 1]) t = u * 2 + 1;if (t != u){heap_swap(t, u);down(t);}
}void up(int u)
{while (u / 2 && h[u] < h[u / 2]){heap_swap(u, u / 2);u >>= 1;}
}int main()
{int s;cin >> s;string op;while (s--){cin >> op;if (op == "I"){int x;cin >> x;n++, m++;hp[n] = m, ph[m] = n;h[n] = x;up(n);}else if (op == "PM") cout << h[1] << endl;else if (op == "DM"){heap_swap(1, n);n--;down(1);}else if (op == "D"){int k;cin >> k;k = ph[k];heap_swap(k, n);n--;down(k), up(k);}else{int k, x;cin >> k >> x;k = ph[k];h[k] = x;down(k), up(k);}}return 0;
}