PPMM

代码

#include<cstdio>
using namespace std;
 
const int N = 1000000 , INF = 2e9;
int n , m , x , head = 1 , tail , p , s;
char opt[5];
 
inline int read()
{
	char ch = getchar();
	int res = 0 , f = 1;
	for(; ch < '0' || ch > '9'; ch = getchar()) if (ch == '-') f = -f;
	for(; ch >= '0' && ch <= '9'; ch = getchar()) res = (res << 3) + (res << 1) + ch - '0';
	return res * f;
}
 
inline int my_m(int x , int y , int o)
{
	if (!o) return x > y ? x : y;
	if (o) return x < y ? x : y;
}
 
struct tree{
	int top;
	int tr[(N << 2) + 5][3];
	inline void change(int l , int r , int k , int x , int v)
	{
		if (l == r && l == x)
		{
			tr[k][0] = tr[k][1] = v;
			return;
		}
		int mid = (l + r) >> 1;
		if (x <= mid) change(l , mid , k << 1 , x , v);
		else change(mid + 1 , r , k << 1 | 1 , x , v);
		tr[k][0] = my_m(tr[k << 1][0] , tr[k << 1 | 1][0] , 0);//Max
		tr[k][1] = my_m(tr[k << 1][1] , tr[k << 1 | 1][1] , 1);//Min
	}
	inline int query(int l , int r , int k , int x , int y , int o) 
	{
		if (l >= x && r <= y) return tr[k][o];
		int mid = (l + r) >> 1 , res = INF;
		if (!o) res = -res;
		if (x <= mid) res = my_m(res , query(l , mid , k << 1 , x , y , o) , o);
		if (y > mid) res = my_m(res , query(mid + 1 , r , k << 1 | 1 , x , y , o) , o);
		return res;	
	}
}f;
 
int main()
{
//	freopen("PPMM.in" , "r" , stdin);
//	freopen("PPMM.out" , "w" , stdout);
	n = read();
	m = n;
	while (m--)
	{
		opt[1] = getchar();
		while (opt[1] != 'P' && opt[1] != 'M') opt[1] = getchar();
		opt[2] = getchar() , opt[3] = getchar();;
		if (opt[1] == 'P' && opt[2] == 'U') 
		{
			x = read();
			if (p == 1) x = -x;
			tail++ , s++;
			f.change(1 , n , 1 , tail , x);
		}
		if (s == 0) continue;
		if (opt[1] == 'P' && opt[2] == 'O') head++ , s--;
		else if (opt[1] == 'M' && opt[2] == 'I') p ^= 1;
		else
		if (opt[1] == 'M' && opt[2] == 'A')
		{
			if (p == 0) printf("%d\n" , f.query(1 , n , 1 , head , tail , 0));//Max
			else printf("%d\n" , -1 * f.query(1 , n , 1 , head , tail , 1));//Min
		}
	}
}