ENG  RUSTimus Online Judge
Online Judge
Problems
Authors
Online contests
About Online Judge
Frequently asked questions
Site news
Webboard
Links
Problem set
Submit solution
Judge status
Guide
Register
Update your info
Authors ranklist
Current contest
Scheduled contests
Past contests
Rules
back to board

Discussion of Problem 1126. Magnetic Storms

Why Time Limit? complexity (n-m)*log(m)
Posted by Marko Tintor (marko@pkj.co.yu) 20 Jul 2002 17:55
Idea:
Using pointer connected heap and queue.
Heap for maximum element.
Queue to find element what needs to be extracted from heap.

#include <fstream.h>
ifstream fin("magnetic.dat");
//#define fin cin
const int max=14001;
short m, value[max], queue[max], heap[max+1], s,c,a;

void heap_swap(short a, short b)
{
    short x;
    x=heap[a];
    heap[a]=heap[b];
    heap[b]=x;

    x=queue[heap[a]];
    queue[heap[a]]=queue[heap[b]];
    queue[heap[b]]=x;
}

void push()
{
    short e=(s+c)%max;
    value[e]=a;
    queue[e]=++c;
    heap[c]=e;

    short k=c;
    while(k>1 && value[heap[k>>1]]<value[heap[k]])
    {
        heap_swap(k>>1,k);
        k=k>>1;
    }
}

void pop()
{
    cout << value[heap[1]] << endl;
    short k=queue[s];
    s++; s%=max;
    heap_swap(k,c--);

    while(k>1 && value[heap[k>>1]]<value[heap[k]])
    {
        heap_swap(k>>1,k);
        k=k>>1;
    }

    short l=k<<1, m;
    while(l<=c)
    {
        m=k;
        if(value[heap[l]]>value[heap[m]]) m=l;
        if(l+1<=c && value[heap[l+1]]>value[heap[m]]) m=l+1;

        if(m==k) break;
        heap_swap(m,k);
        k=m; l=k<<1;
    }
}

void main()
{
    fin >> m;
    for(int i=0; i<m; i++) {fin >> a; push();}
    while(1)
    {
        pop();
        fin >> a; if(a==-1) break;
        push();
    }
}