poj 2823 单调队列

思路：裸的单调队列。

#include<iostream>

#include<cstring>

#include<cstdio>

#include<algorithm>

#define Maxn 1000010

using namespace std;

int n,k,que[Maxn],num[Maxn],head,rear;

int main()

{

    int i,j,a;

    while(scanf("%d%d",&n,&k)!=EOF)

    {

        head=1;

        rear=0;

        for(i=1;i<=n;i++)

            scanf("%d",num+i);

        for(i=1;i<=k;i++)

        {

            while(rear>=head&&num[que[rear]]>=num[i])

                rear--;

            que[++rear]=i;

        }

        printf("%d",num[que[head]]);

        for(i=k+1;i<=n;i++)

        {

            if(i-que[head]>=k)

                head++;

             while(rear>=head&&num[que[rear]]>=num[i])

                rear--;

                que[++rear]=i;

                printf(" %d",num[que[head]]);

        }

        printf("\n");

        head=1;

        rear=0;

        for(i=1;i<=k;i++)

        {

            while(rear>=head&&num[que[rear]]<=num[i])

                rear--;

            que[++rear]=i;

        }

        printf("%d",num[que[head]]);

        for(i=k+1;i<=n;i++)

        {

            if(i-que[head]>=k)

                head++;

             while(rear>=head&&num[que[rear]]<=num[i])

                rear--;

                que[++rear]=i;

                printf(" %d",num[que[head]]);

        }

        printf("\n");

    }

    return 0;

}