POJ2823(Sliding Window)

题目链接

经典单调队列题。

View Code

 1 #include <stdio.h>

 2 #define N 1000005

 3 int a[N];

 4 int q[N],front,rear;

 5 int main()

 6 {

 7     int i,n,k;

 8     while(~scanf("%d%d",&n,&k))

 9     {

10         for(i=0;i<n;i++)    scanf("%d",&a[i]);

11         front=rear=0;

12         for(i=0;i<n;i++)

13         {

14             while(front<rear&&a[i]<=a[q[rear-1]])  rear--;

15             q[rear++]=i;

16             while(i-q[front]+1>k)   front++;

17             if(i==k-1)    printf("%d",a[q[front]]);

18             else if(i>k-1)    printf(" %d",a[q[front]]);

19         }

20         printf("\n");

21         front=rear=0;

22         for(i=0;i<n;i++)

23         {

24             while(front<rear&&a[i]>=a[q[rear-1]])  rear--;

25             q[rear++]=i;

26             while(i-q[front]+1>k)   front++;

27             if(i==k-1)    printf("%d",a[q[front]]);

28             else if(i>k-1)    printf(" %d",a[q[front]]);

29         }

30         printf("\n");

31     }

32     return 0;

33 }