Cod sursa(job #2176158)

Utilizator codrin18Diac Eugen Codrin codrin18 Data 16 martie 2018 21:16:49
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.19 kb
#include <stdio.h>
#include <vector>
#include <fstream>
using namespace std;

#define maxn 100010

int N, M, L, Start;
vector <int> A[maxn];
int G[maxn], S[maxn], Cost[maxn];

void BFS(int nod)
{
    int i, j;

    for (int i=1;i<=maxn;i++)
    {
        Cost[i]=-1;
    }

    //  Introduc nodul de start in coada
    L = 1;
    Cost[nod] = 0;
    S[L] = nod;

    for (i = 1; i <= L; i++) //  Elimin pe rand nodurile din coada
        for (j = 0; j < G[S[i]]; j++)    //  Parcurg vecinii nodului ce urmeaza sa fie eliminat
            if (Cost[A[S[i]][j]] == -1)
            {
                //  Adaug vecinii nevizitati in coada si le calculez distanta
                S[++L] = A[S[i]][j];
                Cost[S[L]] = Cost[S[i]] + 1;
            }
}

int main()
{
    ifstream f("bfs.in");
    ofstream g("bfs.out");
    int i, x, y;

    f>>N>>M>>Start;

    //  Citesc arcele si retin graful sub forma de lista de vecini

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

    for (i = 1; i <= N; i++)
        G[i] = A[i].size();

    BFS(Start);

    for (i = 1; i <= N; i++)
        g<<Cost[i]<<" ";

    return 0;
}