POJ 2838 单调队列

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 using namespace std;
 5 int n,k;
 6 int a[1000005];
 7 int ddq[1000005];
 8 void min()
 9 {
10     int head=1,tail=0;
11     for(int i=0;i<k-1;i++)
12     {
13         while(head<=tail&&a[ddq[tail]]>=a[i])
14         tail--;
15         tail++;
16         ddq[tail]=i;
17     }
18     for(int i=k-1;i<n;i++)
19     {
20         while(head<=tail&&a[ddq[tail]]>=a[i])
21         tail--;
22         tail++;
23         ddq[tail]=i;
24         while(ddq[head]<i-k+1)
25         head++;
26         printf("%d",a[ddq[head]]);
27         if(i==n-1) printf("\n");
28         else printf(" ");
29 
30     }
31 }
32 void max()
33 {
34     int head=1,tail=0;
35     for(int i=0;i<k-1;i++)
36     {
37         while(head<=tail&&a[ddq[tail]]<=a[i])
38         tail--;
39         tail++;
40         ddq[tail]=i;
41     }
42     for(int i=k-1;i<n;i++)
43     {
44         while(head<=tail&&a[ddq[tail]]<=a[i])
45         tail--;
46         tail++;
47         ddq[tail]=i;
48         while(ddq[head]<i-k+1)
49         head++;
50         printf("%d",a[ddq[head]]);
51         if(i==n-1)
52         printf("\n");
53         else printf(" ");
54     }
55 }
56 int main()
57 {
58     while(scanf("%d%d",&n,&k)!=EOF)
59     {
60         memset(ddq,0,sizeof(ddq));
61         memset(a,0,sizeof(a));
62         for(int i=0;i<n;i++)
63         scanf("%d",&a[i]);
64         min();
65         max();
66     }
67     return 0;
68 }