Cod sursa(job #1648384)

Utilizator crysstyanIacob Paul Cristian crysstyan Data 11 martie 2016 09:51:34
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.99 kb
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>
#define NMAX 100005
#define inf 2000000000

using namespace std;

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

int i, n, m, start, d[NMAX], x, y;
vector < int > v[NMAX];
bool visited[NMAX];
queue < int > q;

void BFS()
{
    q.push(start);
    visited[NMAX] = 1;

    while (!q.empty())
    {
        int curr = q.front();
        q.pop();

        for (auto & it : v[curr])
            if (!visited[it])
        {
            d[it] = min(d[it], d[curr] + 1);
            q.push(it);
            visited[it] = 1;
        }
    }
}

int main()
{
    f >> n >> m >> start;

    for (i = 1; i <= m; ++ i)
    {
        f >> x >> y;
        v[x].push_back(y);
    }

    for (i = 1; i <= n; ++ i)
        d[i] = inf;
    d[start] = 0;

    BFS();

    for (i = 1; i <= n; ++ i)
        if (d[i] == inf)
            g << "-1 ";
        else
            g << d[i] << " ";
    return 0;
}