信息学奥赛一本通T1597-滑动窗口-题解（C++双指针）

#include<cstdio>
#include<algorithm>
using std::lower_bound;
inline bool f(const int*a,const int*b){return *a<*b;}
inline bool g(const int*a,const int*b){return *a>*b;}
int main(){
    int n,k;
    scanf("%d%d",&n,&k);
    int*a=new int[n],*i=a,*j=a+n,**b=new int*[n],**x=b,**y=b;
    while(i!=j)scanf("%d",i++);
    for(i=a,j=a+~-k;i!=j;*y++=i++)
        y=lower_bound(x,y,i,f);
    for(j=a+n;i!=j;printf("%d ",**x)){
        if(x!=y&&*x+k==i)++x;
        y=lower_bound(x,y,i,f);
        *y++=i++;
    }
    x=y=b;
    putchar('\n');
    for(i=a,j=a+~-k;i!=j;*y++=i++)
        y=lower_bound(x,y,i,g);
    for(j=a+n;i!=j;printf("%d ",**x)){
        if(x!=y&&*x+k==i)++x;
        y=lower_bound(x,y,i,g);
        *y++=i++;
    }
    delete[]b;
    delete[]a;
}