Cod sursa(job #2160565)

Utilizator marcdariaDaria Marc marcdaria Data 11 martie 2018 13:20:47
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.91 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int MaxN = 100005;
int N, M, S;
vector<int> G[MaxN];
queue<int> Q;
int d[MaxN];

void Read();
void BFS(int x);

int main()
{
    Read();

    for(int i = 1; i <= N; ++i)
        d[i] = -1;

    BFS(S);

    for(int i = 1; i <= N; ++i)
        fout << d[i] << " ";
    fout << '\n';

    fout.close();
    return 0;
}

void Read()
{
    fin >> N >> M >> S;
    while(M--)
    {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
    }
    fin.close();
}
void BFS(int x)
{
    d[x] = 0;
    Q.push(x);

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

        for(const int y : G[new_x])
            if(d[y] == -1)
            d[y] += d[new_x] + 2, Q.push(y);
    }
}