Cod sursa(job #1904883)

Utilizator andrei_diaconuAndrei Diaconu andrei_diaconu Data 5 martie 2017 20:28:22
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.35 kb
#include <fstream>
#include <vector>
#include <queue>

#define NMax 100010
#define INF 1000000000

using namespace std;

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

int nodes, edges, dist[NMax], mark[NMax];
vector< pair<int, int> > G[NMax];

class less_functor {
public:
	bool operator()(pair<int, int> p1, pair<int, int> p2) {
		return p1.second > p2.second;
	}
};
priority_queue < pair<int, int>, vector< pair<int, int> >, less_functor > H;

void dijkstra(int source)
{
	for (int i = 1; i <= nodes; i++)
		dist[i] = INF;
	dist[source] = 0;

	H.push(make_pair(source, 0));

	while (!H.empty()) {
		while (!H.empty() && mark[H.top().first] == true)
			H.pop();
		if (H.empty())
			break;
		
		pair<int, int> crtNode = H.top();
		H.pop();

		mark[crtNode.first] = true;

		for (auto node : G[crtNode.first]) {
			if (!mark[node.first] && dist[node.first] > dist[crtNode.first] + node.second) {
				dist[node.first] = dist[crtNode.first] + node.second;
				H.push(make_pair(node.first, dist[node.first]));
			}
		}

	}
}

int main()
{
	f >> nodes >> edges;

	int n1, n2, c;
	for (int i = 1; i <= edges; i++) {
		f >> n1 >> n2 >> c;
		G[n1].push_back(make_pair(n2, c));
	}

	dijkstra(1);

	for (int i = 2; i <= nodes; i++) {
		if (dist[i] != INF)
			g << dist[i] << ' ';
		else
			g << 0 << ' ';
	}
}