poj 2823:Sliding Window

解题思路：

单调队列

参考：http://blog.csdn.net/heart_dash/article/details/7786258

#include<iostream>
using namespace std;

int a[1000010];
int queue[1000010];
int n,m;

void min_que()
{
int head = 1;
int tail = 0;
for(int i=1;i<=m;i++)
{
while(head<=tail && a[queue[tail]]>a[i])
tail--;
tail++;
queue[tail] = i;
}
for(int i=m;i<=n;i++)
{
while(head<=tail && a[queue[tail]]>a[i])
tail--;
tail++;
queue[tail] = i;
while(queue[head]<i-m+1) head++;
cout<<a[queue[head]]<<" ";
}
cout<<endl;
return;
}

void max_que()
{
int head = 1;
int tail = 0;
for(int i=1;i<=m;i++)
{
while(head<=tail && a[queue[tail]]<a[i])
tail--;
tail++;
queue[tail] = i;
}
for(int i=m;i<=n;i++)
{
while(head<=tail && a[queue[tail]]<a[i])
tail--;
tail++;
queue[tail] = i;
while(queue[head]<i-m+1) head++;
cout<<a[queue[head]]<<" ";
}
cout<<endl;
return;
}

int main()
{
cin>>n>>m;
for(int i=1;i<=n;i++)
cin>>a[i];
min_que();
max_que();
return 0;
}