POJ2823 Sliding Window

Initiate — Thu, 08 Apr 2010 13:03:00 GMT

方法：建两个堆，同时维护一个大根堆和一个小根堆
用一对指针就行卡位
弹出的时候如果在这个区间就记录下来，如果不在区间内就扔掉。

#include<iostream>
using namespace std;
int a[1000010];
int minout[1000010],maxout[1000010];
int n,k;
struct node{
    int key;
    int pla;
};
struct heap//堆
{
    int size;
    struct node elem[2000010];
    }minh,maxh;

void insertmin(int x,int p)
{
     int i= ++minh.size;
     while(minh.elem[i/2].key > x)
     {
         minh.elem[i]=minh.elem[i/2];
        i /=2;
    }
    minh.elem[i].key=x;
    minh.elem[i].pla=p;
}

void deletemin()
{
     int i,child,last,place;
     last=minh.elem[minh.size].key;
     place=minh.elem[minh.size].pla;
     minh.size--;
     for(i=1;i*2 <= minh.size;i = child)
     {
        child=2*i;
        if(child != minh.size && minh.elem[child+1].key < minh.elem[child].key )
            child++;
        if( last > minh.elem[child].key )
            minh.elem[i] = minh.elem[child];
        else break;
        }
    minh.elem[i].key=last;
    minh.elem[i].pla=place;
}

void insertmax(int x,int p)
{
     int i= ++maxh.size;
     while(maxh.elem[i/2].key < x)
     {
         maxh.elem[i]=maxh.elem[i/2];
        i /=2;
    }
    maxh.elem[i].key=x;
    maxh.elem[i].pla=p;
}

void deletemax()
{
     int i,child,last,place;
     last=maxh.elem[maxh.size].key;
     place=maxh.elem[maxh.size].pla;
     maxh.size--;
     for(i=1;i*2 <= maxh.size;i = child)
     {
        child=2*i;
        if(child != maxh.size && maxh.elem[child+1].key > maxh.elem[child].key )//
            child++;
        if( last < maxh.elem[child].key )//
            maxh.elem[i] = maxh.elem[child];
        else break;
        }
    maxh.elem[i].key=last;
    maxh.elem[i].pla=place;
}
void cal()
{
    int i;
    minh.size=0;
    minh.elem[0].key=-INT_MAX;
    maxh.size=0;
    maxh.elem[0].key=INT_MAX;
    for(i=1;i<=k;i++)
        {
            insertmin(a[i],i);
            insertmax(a[i],i);
            }
    int p1=1,p2=k;
    while(p2<=n)
    {
        while(minh.elem[1].pla < p1 || minh.elem[1].pla>p2)
            deletemin();
        while(maxh.elem[1].pla < p1 || maxh.elem[1].pla>p2)
            deletemax();
        minout[p1]=minh.elem[1].key;
        maxout[p1]=maxh.elem[1].key;
        p1++;
        p2++;
        insertmin(a[p2],p2);
        insertmax(a[p2],p2);
        }
}
int main()
{
    int i;
    scanf("%d%d",&n,&k);
    for(i=1;i<=n;i++)
        scanf("%d",&a[i]);
    cal();
    for(i=1;i<=n-k;i++)
        printf("%d ",minout[i]);
    printf("%d\n",minout[n-k+1]);
    for(i=1;i<=n-k;i++)
        printf("%d ",maxout[i]);
    printf("%d\n",maxout[n-k+1]);
    }

Initiate 2010-04-08 21:03 发表评论

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POJ2823 Sliding Window