Cod sursa(job #2754666)

Utilizator bia_bobesBobes Bianca bia_bobes Data 26 mai 2021 11:30:24
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.94 kb
#include <iostream>
#include <vector>
#include <fstream>
#include <queue>
#define NMAX 100005
using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");

int n, m, st ,a[100005];

vector <int > graph[NMAX];
queue <pair < int ,int > > q;
void citire()
{
    fin >> n >> m >> st;

    for(int i = 1; i <= n; i++)
        a[i] = -1;
    for(int i = 0; i < m; i++)
    {
        int x,y;
        fin >> x >> y;
        graph[x].push_back(y);
    }
}

void bfs(){
    a[st] = 0;
    q.push({st, 0});
    while(!q.empty()){
        int vf = q.front().first;
        int lc = q.front().second + 1;
        for(auto &v : graph[vf])
            if(a[v] == -1){
                q.push({v, lc});
                a[v] = lc;
            }
        q.pop();
    }
}
void afisare()
{
    for(int i = 1; i <= n; i++)
        fout <<a[i] << " ";
}
int main()
{
   citire();
   bfs();
   afisare();
    return 0;
}