Cod sursa(job #1651414)

Utilizator EdyOnuEdy Onu EdyOnu Data 13 martie 2016 11:28:45
Problema Algoritmul lui Dijkstra Scor 80
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 50001
#define oo 2000000000
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)
{
    for(int i=1;i<=N;++i)D[i]=oo;
    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);
    }
    viz[1]=1;
    while(!H.empty()){
        while(!H.empty()&&viz[H.top()])H.pop();
        if(H.empty())break;
        start=H.top();
        viz[start]=1;
        H.pop();
        for(it=G[start].begin();it!=G[start].end();++it)
            if(!viz[it->first]&&D[it->first]>it->second+D[start]){
                D[it->first]=it->second+D[start];
                H.push(it->first);
            }
    }
 FILE *fout=fopen("dijkstra.out","w");
 for(int i=2;i<=N;++i)
  if(D[i]==oo)fprintf(fout,"0 ");
  else fprintf(fout,"%d ",D[i]);
}
int main()
{
    ReadData();
    Dijkstra(1);
    return 0;
}