POJ 2823 Sliding Window 单调队列

这道题就是用单调队列来维护，但是用G++交TLE，用c++5000多ms，真是囧...代码很丑，就凑合着看吧
#include<stdio.h>
int a[1000009],que[1000009];
int main(){
	int n,k,i,head,tail,flag=1,f;
	scanf("%d %d",&n,&k);
	for(i=1;i<=n;i++)
		scanf("%d",&a[i]);
	head=1;tail=0;
	f=1;
	for(i=1;i<=n;i++){
		while(tail>=head && a[i]<a[que[tail]])	
			tail--;
		que[++tail]=i;
		if(i>=k){
			if(que[head]<f)
				head++;
			if(flag){
				printf("%d",a[que[head]]);
				flag=0;
			}
			else
				printf(" %d",a[que[head]]);
			f++;
		}
	}
	printf("\n");

	head=1;tail=0;
	flag=1;
	f=1;
	for(i=1;i<=n;i++){
		while(tail>=head && a[i]>a[que[tail]])	
			tail--;
		que[++tail]=i;
		if(i>=k){
			if(que[head]<f)
				head++;
			if(flag){
				printf("%d",a[que[head]]);
				flag=0;
			}
			else
				printf(" %d",a[que[head]]);
			f++;
		}
	}
	printf("\n");
}