Cod sursa(job #1714767)

Utilizator Alexghita96Ghita Alexandru Alexghita96 Data 9 iunie 2016 12:53:06
Problema BFS - Parcurgere in latime Scor 80
Compilator cpp Status done
Runda Arhiva educationala Marime 1.15 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <cstring>

#define NMAX 100005
#define INF 0x3F3F3F3F

using namespace std;

int N, M, S, ans[NMAX];
vector <int> graph[NMAX];

void read() {
    int x, y;

    cin >> N >> M >> S;

    for (int i = 1; i <= M; ++i) {
        cin >> x >> y;
        graph[x].push_back(y);
    }

    memset(ans, INF, sizeof(ans));
    ans[S] = 0;
}

void bfs(int root) {
    queue <int> q;
    vector <int> :: iterator it;
    int node;

    q.push(root);

    while (!q.empty()) {
        node = q.front();
        q.pop();

        for (it = graph[node].begin(); it != graph[node].end(); ++it) {
            if (ans[*it] > ans[node] + 1) {
                ans[*it] = ans[node] + 1;
                q.push(*it);
            }
        }
    }
}

void print() {
    for (int i = 1; i <= N; ++i) {
        if (ans[i] == INF) {
            cout << "-1 ";
            continue;
        }
        cout << ans[i] << " ";
    }
}

int main() {
    freopen("bfs.in", "r", stdin);
    freopen("bfs.out", "w", stdout);

    read();
    bfs(S);
    print();
}