Cod sursa(job #3245670)

Utilizator gabrielvGabriel Vanca gabrielv Data 30 septembrie 2024 00:52:12
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.03 kb
#include <cstdio>
#include <vector>
#include <queue>

using namespace std;

#define NMAX 100005

int N, M, S;

int dist[NMAX];

vector<int>           G[NMAX];
vector<int>::iterator it;

queue<int> Q;

void Read()
{
    freopen("bfs.in", "r",stdin);
    scanf("%d%d%d", &N, &M, &S);

    for (int i = 1; i <= M; i++)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        G[x].push_back(y);
    }
}

void BFS()
{
    for (int i  = 1; i <= N; i++)
        dist[i] = -1;

    Q.push(S);
    dist[S] = 0;

    while (!Q.empty())
    {
        int nod = Q.front();
        Q.pop();

        for (it = G[nod].begin(); it != G[nod].end(); it++)
        {
            if (dist[*it] != -1)
                continue;
            dist[*it] = dist[nod] + 1;
            Q.push(*it);
        }
    }
}

void Print()
{
    freopen("bfs.out", "w",stdout);

    for (int i = 1; i <= N; i++)
        printf("%d ", dist[i]);
}

int main()
{
    Read();
    BFS();
    Print();
    return 0;
}