Cod sursa(job #2616548)

Utilizator pro119Manea Dumitru pro119 Data 18 mai 2020 20:35:29
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.99 kb
#include <bits/stdc++.h>
using namespace std;
#define ll long long

const int mxN=1e5+1;
int n,m,start,x,y;
vector <int> g[mxN];
int viz[mxN];

void bfs (int start){
    queue <int> q;
    q.push(start);
    viz[start]=1;

    while(!q.empty()){
        int node = q.front();
        q.pop();
        for (int i=0; i<g[node].size(); i++){
            if (!viz[g[node][i]]){
                viz[g[node][i]]=viz[node]+1;
                q.push(g[node][i]);
            }
        }
    }

}

int main()
{
    ifstream cin("bfs.in");
    ofstream cout("bfs.out");
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    //read
    cin>>n>>m>>start;
    for (int i=0; i<m; i++){
        cin>>x>>y;
        g[x].push_back(y);
    }

    //solve
    bfs(start);

    //write
    for (int i=1; i<=n; i++){
        if (i==start) cout<<0<<" ";
        else{
            if (viz[i]==0) cout<<-1<<" ";
            else cout<<viz[i]-1<<" ";
        }
    }
    return 0;
}