Cod sursa(job #2773203)

Utilizator alex_unixPetenchea Alexandru alex_unix Data 5 septembrie 2021 16:12:43
Problema BFS - Parcurgere in latime Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.97 kb
#include <fstream>
#include <vector>
#include <queue>
#include <cstdlib>

const int MAX_N = 100001;
const int MAX_M = 1000001;

int n, m, s;
std::vector<int> graph[MAX_N];
std::queue<int> queue;
int cost[MAX_N];

void read()
{
	std::ifstream input("bfs.in");
	input >> n >> m >> s;
	int x, y;
	for (int edge(0); edge < m; ++edge) {
		input >> x >> y;
		graph[x].push_back(y);
	}
	input.close();
}

void print()
{
	std::ofstream output("bfs.out");
	for (int vertex(1); vertex <= n; ++vertex) {
		output << cost[vertex] << ' ';
	}
	output.put('\n');
	output.close();
}

void bfs()
{
	queue.push(s);
	std::memset(static_cast<void*>(cost), 0xff, sizeof(cost));
	cost[s] = 0;
	int vertex;
	while (!queue.empty()) {
		vertex = queue.back();
		queue.pop();
		for (auto node : graph[vertex]) {
			if (cost[node] == -1) {
				cost[node] = cost[vertex] + 1;
				queue.push(node);
			}
		}
	}
}

int main()
{
	read();
	bfs();
	print();
	return 0;
}