Shortest Routes I

cc1plus: error: '::main' must return 'int'

#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define debug(x) cerr << #x << ": " << x << endl;

struct route {
    ll dest;
    ll length;
};

ll main() {
    ll n,m;
    cin >> n >> m;

    vector<vector<route>> routes (n+1);
    ll a, b, c;
    for (ll i = 0; i < m; i++)
    {
        cin >> a >> b >> c;
        routes[a].push_back({b,c});
    }

    // DIJKSTRA ALGORITHM
    vector<bool> processed (n+1, false);
    vector<ll>  distances (n+1, INT_MAX); distances[1] = 0;
    priority_queue<pair<ll,ll>,
                   vector<pair<ll,ll>>,
                   greater<pair<ll,ll>>> q;
    q.push({0,1});
    while (q.empty() == false) {
        a = q.top().second; q.pop();
        if (processed[a]) continue;
        processed[a] = true;
        for (route& r : routes[a]) {
            if (distances[a] + r.length < distances[r.dest]) {
                distances[r.dest] = distances[a] + r.length;
                q.push({distances[r.dest], r.dest});
            }
        }
    }

    for (ll i = 1; i <= n; i++)
    {
        cout << distances[i] << ' ';
    }
    cout << endl;    
    

    return 0;
}