Cod sursa(job #1705496)

Utilizator alex95panPandelea Alexandru alex95pan Data 20 mai 2016 18:11:59
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.97 kb
#include <iostream>
#include <vector>
#include <fstream>
#include <queue>
#include <climits>

using namespace std;

vector<int> g[100001];
int dist[100001];
int n;

void bfs(int rad)
{
	queue<int> q;

	for(int i=1;i<=n;i++)
    {
        dist[i]=-1;
    }

    dist[rad] = 0;
    q.push(rad);

    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        for(int i=0; i<g[u].size();i++)
        {
            if(dist[g[u][i]]==-1)
            {
                q.push(g[u][i]);
                dist[g[u][i]] = dist[u] + 1;
            }
        }
    }
}

int main()
{
    int m,s;
    fstream f, out;
	f.open("bfs.in", ios::in);
	out.open("bfs.out", ios::out);

    f >> n >> m >> s;
	for (int i = 0; i < m; i++)
	{
		int x, y;
		f >> x >> y;

		g[x].push_back(y);
	}

    bfs(s);

    for (int i=1;i<=n;i++)
        if(dist[i] == INT_MAX)
            out<<"-1 ";
        else
            out<<dist[i]<<" ";

    return 0;
}