Cod sursa(job #1651394)

Utilizator EdyOnuEdy Onu EdyOnu Data 13 martie 2016 11:06:49
Problema Algoritmul lui Dijkstra Scor 60
Compilator cpp Status done
Runda Arhiva educationala Marime 1.49 kb
#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <utility>
#include <bitset>
#define NMAX 25001
#define oo 250000*1001
using namespace std;
vector < pair<long,long> >G[NMAX];
int N,M;

void ReadData()
{
    FILE *fin=fopen("dijkstra.in","r");
    fscanf(fin,"%d %d",&N,&M);
    for(int i=1;i<=M;++i){
        int x,y,c;
        fscanf(fin,"%d %d %d",&x,&y,&c);
        G[x].push_back(make_pair(y,c));
    }
    fclose(fin);
}
long D[NMAX];

class MinHeap
{
public:
    bool operator()(long a,long b)
    {
        return D[a]>D[b];
    }
};

priority_queue<long,vector<long>,MinHeap>H;
bitset<NMAX>viz;

void Dijkstra(int start)
{
    viz[start]=true;
    vector< pair<long,long> >::iterator it;
    for(it=G[start].begin();it!=G[start].end();++it){
        D[it->first]=it->second;
        H.push(it->first);
    }

   while(!H.empty()){
      while(!H.empty())
       if(!viz[H.top()])break;
       else H.pop();
      if(H.empty())break;
      start=H.top();
      H.pop();
      viz[start]=true;
      for(it=G[start].begin();it!=G[start].end();++it)
        if( !viz[it->first] && (  D[start]+it->second  <  D[it->first]  ||  !D[it->first] ) )
        {
            D[it->first]=it->second+D[start];
            H.push(it->first);
        }
    }
 FILE *fout=fopen("dijkstra.out","w");
 for(int i=2;i<=N;++i)fprintf(fout,"%d ",D[i]);
 fclose(fout);
}
int main()
{
    ReadData();
    Dijkstra(1);
    return 0;
}