Cod sursa(job #1880241)

Utilizator robertispasIspas Robert robertispas Data 15 februarie 2017 17:16:41
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.82 kb
#include <fstream>
#include <vector>

using namespace std;

ifstream in("bfs.in");
ofstream out("bfs.out");

const int N = 1000005;
vector <int> a[N];
int n, m, st, l;
int q[N], d[N];

void citire()
{
    int i, x, y;
    in>>n>>m>>st;
    for(i = 1; i <= m; i++)
    {
        in>>x>>y;
        a[x].push_back(y);
    }
    for(i = 1; i <= n; i++)
        d[i] = -1;
    in.close();
}

void bfs(int x0)
{
    int p = 0, u = -1, x, y;
    q[++u] = x0;
    d[x0] = 0;
    while(p <= u)
    {
        x = q[p++];
        for(int i = 0; i < a[x].size(); i++)
        {
            y = a[x][i];
            if(d[y] == -1)
            {
                q[++u] = y;
                d[y] = 1 + d[x];
            }
        }
    }
}

int main()
{
    citire();
    bfs(st);
    for(int i = 1; i <= n; i++)
        out<<d[i]<<" ";
    return 0;
}