Cod sursa(job #1830456)

Utilizator snappyRazvan Alin snappy Data 16 decembrie 2016 19:15:53
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.8 kb
#include <bits/stdc++.h>
using namespace std;

const int oo = (1 << 30);
const int N = 100005;

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

vector<int> v[N];
queue<int> q;
int d[N];
bool viz[N];
int n, m, x, y, i, s;

void bf(int s) {
    for(i = 1; i <= n; i++)
        d[i] = oo;

    d[s] = 0;
    viz[s] = 1;

    q.push(s);
    while(!q.empty()) {
        x = q.front(); q.pop();
        for(auto it : v[x])
            if(!viz[it]) {
                d[it] = d[x] + 1;
                q.push(it);
                viz[it] = 1;
            }
    }

}

int main()
{
    f >> n >> m >> s;
    for(; m; m--) {
        f >> x >> y;
        v[x].push_back(y);
    }

    bf(s);

    for(i = 1; i <= n; i++)
        g << (d[i] == oo ? -1 : d[i]) << ' ';

    return 0;
}