Cod sursa(job #2590933)

Utilizator pregoliStana Andrei pregoli Data 29 martie 2020 13:10:21
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.06 kb
#include <bits/stdc++.h>
#define newline '\n'
using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
///***********************

const int NMAX = 1e5 + 3;
int n, m, s;
vector<int> graph[NMAX];
int ans[NMAX];

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

void bfs(int node)
{
    fill(ans, ans + n + 1, -1);
    queue<int> bfsQ;
    vector<bool> vis(n + 3, false);
    ans[node] = 0;
    vis[node] = true;
    bfsQ.push(node);
    while (!bfsQ.empty())
    {
        int cnode = bfsQ.front();
        bfsQ.pop();
        for (auto nei : graph[cnode])
        {
            if (!vis[nei])
            {
                vis[nei] = true;
                bfsQ.push(nei);
                ans[nei] = ans[cnode] + 1;
            }
        }
    }
}

void display()
{
    for (int i = 1; i <= n; i++)
        fout << ans[i] << ' ';
}

int main()
{
    read();
    bfs(s);
    display();
    return 0;
}