Cod sursa(job #2425321)

Utilizator malina99oanea ana malina malina99 Data 24 mai 2019 18:34:22
Problema BFS - Parcurgere in latime Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.97 kb
#include <fstream>
#include <queue>
#include <vector>
#include <climits>

using namespace std;

ifstream f("bfs.in");
ofstream g("bfs.out");

int n, s, m;
#define nmax 100000

vector <int> graph[nmax];

void read_data() {
    f >> n >> m;
    f >> s;
    for( int i = 0; i < m; i++ ) {
        int x, y;
        f >> x >> y;
        graph[x].push_back(y);
    }
}

int d[nmax], viz[nmax];

void bfs() {
    queue <int> coada;
    for( int i = 1; i <= n; i++) d[i] = INT_MAX;
    viz[s] = 1;
    coada.push(s); d[s] = 0;
    while( !coada.empty() ) {
        int nod = coada.front(); coada.pop();
        for( auto x : graph[nod] ) {
            if( !viz[x] ) {
                if( d[x] > d[nod] + 1 ) {
                    d[x] = d[nod] + 1;
                    coada.push(x);
                }
            }
        }
    }
}

int main(){
    read_data();
    bfs();
    for( int i = 1; i <= n; i++ ) 
    if( d[i] == INT_MAX ) g << -1 <<" ";
    else
    g << d[i] << " ";
    return 0;
}