Cod sursa(job #2405832)

Utilizator teomdn001Moldovan Teodor teomdn001 Data 15 aprilie 2019 00:15:41
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.18 kb
#include <fstream>
#include <vector>
#include <queue>
#include <fstream>
#include <tuple>
using namespace std;

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

const int Inf = 0x3f3f3f3f;

using PI  = pair<int, int>;
using VP  = vector<PI>;
using VVP = vector<VP>;
using VI  = vector<int>;

int n, m;
VI d;  // d[x] = dist minima de la sursa la nodul x
VVP G;

void CitesteGraf();
void Dijkstra(int x, VI& d);
void AfiseazaDistante(const VI& d);


int main()
{
	CitesteGraf();
	Dijkstra(1, d);
	AfiseazaDistante(d);
}

void Dijkstra(int x, VI& d)
{
	d = VI(n + 1, Inf);
	priority_queue<PI, vector<PI>, greater<PI>> Q; // min-HEAP

	d[x] = 0;
	Q.push({0, x});

	int y, w, dist;
	while (!Q.empty())
	{
		tie(dist, x) = Q.top();
		Q.pop();
		if (dist > d[x])
			continue;

		for (auto& p : G[x])
		{
			tie(y, w) = p;
			if (d[y] > d[x] + w)
			{
				d[y] = d[x] + w;
				Q.push({d[y], y});
			}
		}
	}
}

void AfiseazaDistante(const VI& d)
{
	for (int i = 2; i <= n; ++i)
		fout << d[i] << ' ';
}

void CitesteGraf()
{
    int x, y, w;
    fin >> n >> m;
    G = VVP(n + 1);

    for (int i = 1; i <= m; ++i)
    {
        fin >> x >> y >> w;
        G[x].emplace_back(y, w);
    }
}