Cod sursa(job #1360346)

Utilizator mirceadinoMircea Popoveniuc mirceadino Data 25 februarie 2015 13:53:59
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.18 kb
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<deque>

using namespace std;

#ifdef HOME
const string inputFile = "input.txt";
const string outputFile = "output.txt";
#else
const string problemName = "bfs";
const string inputFile = problemName + ".in";
const string outputFile = problemName + ".out";
#endif

const int INF = (1 << 30);
const int NMAX = 100000 + 5;

int N, M, source;
vector<int> V[NMAX];
int D[NMAX];
bitset<NMAX> viz;
deque<int> Q;

void bfs(int x) {
    int i;

    for(i = 1; i <= N; i++)
        D[i] = INF;

    D[x] = 0;
    viz[x] = 1;
    Q.push_back(x);

    while(!Q.empty()) {
        x = Q.front();
        Q.pop_front();

        for(auto y : V[x])
            if(!viz[y]) {
                D[y] = D[x] + 1;
                viz[y] = 1;
                Q.push_back(y);
            }
    }
}

int main() {
    int i, x, y;

    freopen(inputFile.c_str(), "r", stdin);
    freopen(outputFile.c_str(), "w", stdout);

    scanf("%d%d%d", &N, &M, &source);

    while(M--) {
        scanf("%d%d", &x, &y);
        V[x].push_back(y);
    }

    bfs(source);

    for(i = 1; i <= N; i++)
        printf("%d ", D[i] == INF ? -1 : D[i]);

    return 0;
}