【POJ】2823 Sliding Window

#include<cstdio>
#define MAXN 1000010
int a[MAXN],q[MAXN];
int main()
{
    int n,k,i,j,front,rear;
    while(~scanf("%d%d",&n,&k))
    {
        for(i=1;i<=n;i++)
            scanf("%d",&a[i]);
        front=0;
        rear=-1;
        for(i=1;i<=k;i++)
        {
            for(;front<=rear&&a[q[rear]]>=a[i];rear--);
            q[++rear]=i;
        }
        printf("%d",a[q[front]]);
        for(j=1;i<=n;i++,j++)
        {
            if(front<=rear&&q[front]<=j)
                front++;
            for(;front<=rear&&a[q[rear]]>=a[i];rear--);
            q[++rear]=i;
            printf(" %d",a[q[front]]);
        }
        putchar('\n');
        front=0;
        rear=-1;
        for(i=1;i<=k;i++)
        {
            for(;front<=rear&&a[q[rear]]<=a[i];rear--);
            q[++rear]=i;
        }
        printf("%d",a[q[front]]);
        for(j=1;i<=n;i++,j++)
        {
            if(front<=rear&&q[front]<=j)
                front++;
            for(;front<=rear&&a[q[rear]]<=a[i];rear--);
            q[++rear]=i;
            printf(" %d",a[q[front]]);
        }
        putchar('\n');
    }
    return 0;
}