Cod sursa(job #563429)

Utilizator stinkyStinky si Grasa stinky Data 25 martie 2011 09:06:08
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.25 kb
#include <fstream>
#include <queue>
#include <vector>

using namespace std;

const int N = 50050;
const int INF  = 1000000000;

struct pereche
{
	int nod,cost;
};

vector<pereche> a[N];
priority_queue<pair<int,int> > h;
int n,d[N];
bool s[N];

ifstream in("dijkstra.in");
ofstream out("dijkstra.out");

void citire()
{
	int m,i,x,y,c;
	in>>n>>m;
	for(i=1 ; i<=m ; i++)
	{
		in>>x>>y>>c;
		a[x].push_back((pereche){y,c});
	}
}

void init()
{
	for(int i=0 ; i<=n ; i++)
		d[i] = INF;
}

int vf_cost_min()
{
	while(!h.empty())
	{
		if(!s[h.top().second])
			return h.top().second;
		h.pop();
	}
	return 0;
}

void actualizare(int x)
{
	int c,y;
	for(size_t i=0 ; i<a[x].size() ; i++)
	{
		y = a[x][i].nod;
		c = a[x][i].cost;
		if(d[x] + c < d[y])
		{
			d[y] = d[x] + c;
			h.push(make_pair(-d[y],y));
		}
	}
}

void dijkstra(int x0)
{
	int x;
	d[x0] = 0;
	h.push(make_pair(d[x0],x0));
	for(int i=1 ; i<n ; i++)
	{
		x = vf_cost_min();
		if(d[x] == INF)
			return;
		s[x] = true;
		actualizare(x);
	}
}

void afisare()
{
	for(int i=2 ; i<=n ; i++)
		if(d[i] == INF)
			out<<"0 ";
		else
			out<<d[i]<<" ";
}

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