Cod sursă (job #664137)

#include <bits/stdc++.h>

using namespace std;

const int Nmax = 500000 + 1;
const int Mmax = 600000 + 1;
const int NIL = -1;

struct Edge
{
    int nod;
    int cost;

    int urm;
};

Edge G[2 * Mmax + Nmax];
int head[Nmax];

int dist[Nmax];
queue<int> Q;
bool in_q[Nmax];

int N, M, X;
int contor;

void addEdge(int a, int b, int c)
{
    G[contor] = {b, c, head[a]};
    head[a] = contor++;
}

int main()
{
    ifstream in("evacuare.in");
    ofstream out("evacuare.out");

    ios_base::sync_with_stdio(false);

    in >> N >> M >> X;

    for (int i = 1; i <= N; ++i)
        head[i] = NIL;

    for (int i = 1; i <= M; ++i)
    {
        int a, b;
        in >> a >> b;

        addEdge(a, b, 1);
        addEdge(b, a, 1);
    }

    for (int i = 1; i <= N; ++i)
    {
        int p;
        in >> p;

        addEdge(i, p, 0);
    }

    for (int i = 1; i <= N; ++i)
        dist[i] = numeric_limits<int>::max();

    dist[X] = 0;
    in_q[X] = 1;
    Q.push(X);

    int it = 0;

    while (Q.size())
    {
        int nod = Q.front();
        in_q[nod] = false;
        Q.pop();

        for (int p = head[nod]; p != NIL; p = G[p].urm)
        {
            int v = G[p].nod;
            int cost = G[p].cost;

            if (dist[v] > dist[nod] + cost)
            {
                dist[v] = dist[nod] + cost;

                if (!in_q[v])
                {
                    in_q[v] = true;
                    Q.push(v);
                }
            }
        }
    }

    for (int i = 1; i <= N; ++i)
        out << dist[i] << "\n";

    return 0;
}