Cod sursa(job #2079668)

Utilizator pistvanPeter Istvan pistvan Data 1 decembrie 2017 17:56:44
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1 kb
#include <fstream>
#include <iostream>
#include <vector>
#include <queue>
#define MaxN 100005
using namespace std;

int N, M, S;
vector<int> AdList[MaxN];
int dist[MaxN];

void Read()
{
    ifstream f("bfs.in");
    f>>N>>M>>S;
    int x, y;
    for (int i=1;i<=N;i++)
    {
        AdList[i].push_back(0);
        dist[i]=-1;
    }
    for (int i=0;i<M;i++)
    {
        f>>x>>y;
        AdList[x].push_back(y);
        AdList[x][0]++;
    }
}

void BFS()
{
    dist[S]=0;
    queue<int> q;
    int fr, j;
    q.push(S);
    while (!q.empty())
    {
        fr=q.front();
        for (int i=1;i<=AdList[fr][0];i++)
        {
            j = AdList[fr][i];
            if (dist[j]==-1)
            {
                q.push(j);
                dist[j] = dist[fr]+1;
            }
        }
        q.pop();
    }
}

void Write()
{
    ofstream g("bfs.out");
    for (int i=1;i<=N;i++)
        g<<dist[i]<<' ';
}

int main()
{
    Read();
    BFS();
    Write();
}