Cod sursa(job #2582217)

Utilizator andrei_C1Andrei Chertes andrei_C1 Data 16 martie 2020 15:15:36
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.16 kb
#include <fstream>
#include <iostream>
#include <cstdio>
#include <queue>
#define dim 50005
#define inf (1<<31)-1

using namespace std;

int D[dim];
int n,m,p;
bool viz[dim];
vector < pair<int,int> > G[dim];

class InParser
{
private :
    FILE *fin;
    const int lim=1<<16;
    int pos;
    char *buf;
    void next()
    {
        pos++;
        if(pos==lim)
        {
            fread(buf,1,lim,stdin);
            pos=0;
        }
    }
public :
    InParser(const char *file)
    {
        fin=freopen(file,"r",stdin);
        buf=new char[lim]();
        pos=lim-1;
    }
    InParser& operator >> (int &nr)
    {
        nr=0;
        char sign;
        for(;buf[pos]<'0' || buf[pos]>'9';next())sign=buf[pos];
        for(;buf[pos]>='0' && buf[pos]<='9';next())
            nr=nr*10+buf[pos]-'0';
        if(sign=='-')
            nr=-nr;
        return *this;
    }
};

InParser fin("dijkstra.in");
ofstream fout("dijkstra.out");

class compara
{
public :
    bool operator ()(int x,int y)
    {
        return D[x]>D[y];
    }
};

priority_queue < int, vector<int>, compara > Q;

void citire()
{
    fin>>n>>m;
    for(int i=0,x,y,c;i<m;i++)
    {
        fin>>x>>y>>c;
        G[x].push_back(make_pair(y,c));
    }
}

void dijkstra(int X)
{
//    memset(D,inf,sizeof(D));
    for(int i=1;i<=n;i++)
        D[i]=inf;
    D[X]=0;
    Q.push(X);
    viz[X]=1;
    while(!Q.empty())
    {
        int nod=Q.top();
        Q.pop();
        viz[nod]=0;
        int N=G[nod].size();
        for(int i=0;i<N;i++)
        {
            int vecin=G[nod][i].first;
            int cost=G[nod][i].second;
            if(D[nod]+cost<D[vecin])
            {
                D[vecin]=D[nod]+cost;
                if(!viz[vecin])
                {
                    viz[vecin]=1;
                    Q.push(vecin);
                }
            }
        }
    }
}

void afisare()
{
    for(int i=2;i<=n;i++)
    {
        if(D[i]!=inf)
            fout<<D[i]<<" ";
        else
            fout<<"0 ";
    }
}

int main()
{
    citire();
    dijkstra(1);
    afisare();
    return 0;
}