iVaDq9 - Online C++ Compiler & Debugging Tool

#include <iostream>
#include <vector>
#include <limits>

using namespace std;

const int64_t MAX = 1000010;
const int64_t QSIZE = 3000000;

int64_t N, M, a, b, c, h, inizio, fine;
vector<vector<int64_t>> graph(MAX);
vector<vector<int64_t>> peso(MAX);
vector<int64_t> gsize(MAX, 0);
vector<int64_t> gcapa(MAX, 1);
vector<bool> visited(MAX, false);
vector<int64_t> dist(MAX, numeric_limits<int64_t>::max());
vector<int64_t> S(QSIZE), E(QSIZE), P(QSIZE);
vector<int64_t> q1(QSIZE), q2(QSIZE);

void bfs(int64_t partenza, int64_t arrivo, vector<int64_t>& res) {
    int64_t qhead = 0, qcount = 1, first, second;
    q1[0] = partenza;
    q2[0] = 0;

    fill(visited.begin(), visited.begin() + N, false);

    while (qcount > 0) {
        first = q1[qhead];
        second = q2[qhead];
        qhead = (qhead + 1) % QSIZE;
        qcount--;

        if (visited[first]) {
            if (second < res[first]) {
                res[first] = second;
            } else {
                continue;
            }
        }

        visited[first] = true;
        res[first] = second;

        for (int64_t j = 0; j < gsize[first]; j++) {
            q1[(qhead + qcount) % QSIZE] = graph[first][j];
            q2[(qhead + qcount) % QSIZE] = second + peso[first][j];
            qcount++;
        }
    }
}

int main() {
    cin >> N >> M;
    for (h = 0; h < M; h++) {
        cin >> S[h] >> E[h] >> P[h];
    }

    for (h = 0; h < N; h++) {
        graph[h].resize(1);
        peso[h].resize(1);
        dist[h] = numeric_limits<int64_t>::max();
    }

    for (h = 0; h < M; h++) {
        a = S[h];
        b = E[h];
        c = P[h];

        if (gsize[a] == gcapa[a]) {
            gcapa[a] *= 2;
            graph[a].resize(gcapa[a]);
            peso[a].resize(gcapa[a]);
        }

        graph[a][gsize[a]] = b;
        peso[a][gsize[a]] = c;
        gsize[a]++;
    }

    inizio = 0;
    for (h = 1; h <= N; h++) {
        fine = h;
        bfs(inizio, fine, dist);
    }

    for (h = 0; h < N; h++) {
        if (dist[h] != numeric_limits<int64_t>::max()) {
            cout << dist[h] << ' ';
        } else {
            cout << "-1 ";
        }
    }

    return 0;
}