poj 2823

才发现我的第一道BZ是单调队列。。

发现云神的资料里面有这个的介绍就来水水。。

单调队列由于要去掉队尾就还是用数组好点，而且写起来比STL要好看点

 1 //#include<bits/stdc++.h>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<iostream>
 6 #include<queue>
 7 #define inc(i,l,r) for(int i=l;i<=r;i++)
 8 #define dec(i,l,r) for(int i=l;i>=r;i--)
 9 #define link(x) for(edge *j=h[x];j;j=j->next)
10 #define mem(a) memset(a,0,sizeof(a))
11 #define inf 1e9
12 #define ll long long
13 #define succ(x) (1<<x)
14 #define NM 1000000+5
15 using namespace std;
16 int read(){
17     int x=0,f=1;char ch=getchar();
18     while(!isdigit(ch)){if(ch==‘-‘)f=-1;ch=getchar();}
19     while(isdigit(ch))x=x*10+ch-‘0‘,ch=getchar();
20     return x*f;
21 }
22 int n,m,q[NM],a[NM],qh,qt,k;
23 int main(){
24 //    freopen("data.in","r",stdin);
25     n=read();k=read();
26     inc(i,1,n)a[i]=read();qh=1;
27     inc(i,1,k-1){
28         while(qh<=qt&&a[q[qt]]>=a[i])qt--;
29         q[++qt]=i;
30     }
31     inc(i,k,n){
32         while(qh<=qt&&a[q[qt]]>=a[i])qt--;
33         while(qh<=qt&&q[qh]<i-k+1)qh++;
34         q[++qt]=i;printf("%d ",a[q[qh]]);
35     }
36     printf("\n");mem(q);qh=1;
37     inc(i,1,k-1){
38         while(qh<=qt&&a[q[qt]]<=a[i])qt--;
39         q[++qt]=i;
40     }
41     inc(i,k,n){
42         while(qh<=qt&&a[q[qt]]<=a[i])qt--;
43         while(qh<=qt&&q[qh]<i-k+1)qh++;
44         q[++qt]=i;printf("%d ",a[q[qh]]);
45     }
46     printf("\n");
47     return 0;
48 }