Cod sursa(job #1837412)

Utilizator delta_wolfAndrei Stoica delta_wolf Data 29 decembrie 2016 17:41:55
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.64 kb
#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;

int n,m,nh;
int heap[50003],poz[50003],d[50003];
vector<pair<int, int > > graf[50003];

void sw(int i,int j)
{
    swap(heap[i],heap[j]);
    poz[heap[i]]=i;
    poz[heap[j]]=j;

}

void heapup(int k)
{
    if(k<=1)
        return;
    int t=k/2;
    if (d[heap[k]]<d[heap[t]])
    {
        sw(t,k);
        heapup(t);
    }

}

void heapdw(int k)
{
    int f=2*k;

    if (f<=nh)
    {
        if (f+1<=nh&&d[heap[f+1]]<d[heap[f]])
            f++;

        if (d[heap[f]]<d[heap[k]])
        {
            sw(f,k);
            heapdw(f);
        }

    }
}


int ins()
{
    sw(1,nh);
    poz[heap[nh]]=0;
    nh--;
    return heap[nh+1];
}


void dij(int x)
{
    for(int i=1;i<=n;i++)
        d[i]=1<<30,heap[i]=poz[i]=i;
    d[x]=0;
    nh=n;
    while(nh)
    {
        x=ins();
        heapdw(1);
        for(int i=0;i<graf[x].size();i++)
        {
            if(d[graf[x][i].first]>d[x]+graf[x][i].second&&poz[graf[x][i].first])
            {
                d[graf[x][i].first]=d[x]+graf[x][i].second;
                heapup(poz[graf[x][i].first]);
            }
        }
    }
}

int main()
{
    freopen("dijkstra.in","r",stdin);
    freopen("dijkstra.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(int i=1,x,y,z;i<=m;i++)
    {
        scanf("%d%d%d",&x,&y,&z);
        graf[x].push_back(make_pair(y,z));
    }



    dij(1);

    for(int i=2,j=1<<30;i<=n;i++)
    {
        if(d[i]<j)
            printf("%d ",d[i]);
        else
            printf("0 ");
    }
    return 0;
}