Cod sursa(job #2655150)

Utilizator PaulTPaul Tirlisan PaulT Data 3 octombrie 2020 13:39:20
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.05 kb
#include <fstream>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;

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

const int Inf = 0x3f3f3f3f;
int n, m;
VVP G;
VI d;

void Read();
void Dijkstra(int x, VI& d);
void Write();

int main()
{
	Read();
	Dijkstra(1, d);
	Write();
}

void Write()
{
	ofstream fout("dijkstra.out");
	for (int i = 2; i <= n; i++)
		if (d[i] == Inf)
			fout << "0 ";
		else
			fout << d[i] << ' ';
}

void Dijkstra(int x, VI& d)
{
	d = VI(n + 1, Inf);
	priority_queue<PI, VP, greater<PI>> Q;
	
	d[x] = 0;
	Q.emplace(0, x);
	int y, w, dx;
	while (!Q.empty())
	{
		x = Q.top().second;
		dx = Q.top().first;
		Q.pop();
		if (dx > d[x])
			continue;
		for (PI p : G[x])
		{
			y = p.first;
			w = p.second;
			if (d[y] > d[x] + w)
			{
				d[y] = d[x] + w;
				Q.emplace(d[y], y);
			}
		}
	}
}

void Read()
{
	ifstream fin("dijkstra.in");
	fin >> n >> m;
	G = VVP(n + 1);
	
	int x, y, w;
	for (int i = 0; i < m; i++)
	{
		fin >> x >> y >> w;
		G[x].emplace_back(y, w);
	}
}