Submission #672883

#	Time	Username	Problem	Language	Result	Execution time	Memory
672883		iosif_andrei_	Cities (BOI16_cities)	C++14	0 / 100	6010 ms	15080 KiB

cities

#include <bits/stdc++.h> 
using namespace std;

typedef long long ll;

int n, m, sz, t[100001];
ll d[100001];
vector <pair<int, int>> g[100001];
vector <int> v;
const ll inf = 1000000000000000000;

struct result {

    bitset <100001> f;
    ll cost;

    result()
    {
        f = 0;
        cost = inf;
    }

}a[32];

struct nod {
    int key;

    bool operator < (const nod& aux) const
    {
        return d[key] > d[aux.key];
    }
};

int main() {
    
    cin >> n >> sz >> m;

    for (int i = 1; i <= sz; i++)
    {
        int x;
        cin >> x;
        v.push_back(x);
    } 

    for (int i = 1; i <= m; i++)
    {
        int x, y, cost;
        cin >> x >> y >> cost;
        g[x].push_back({ y, cost });
        g[y].push_back({ x, cost });
    }

    for (int i = 0; i < v.size(); i++)
        a[(1 << i)].f[v[i]] = true, a[(1 << i)].cost = 0;

    priority_queue <nod> Q;

    for (int i = 1; i < (1 << sz); i++)
        for (int j = 1; j < (1 << sz); j++)
        {
            if (i & j)
                continue;

            int aux = (i | j);

            if ((a[i].f & a[j].f).any())
                continue;

            for (int k = 1; k <= n; k++)
                if (a[i].f[k])
                    d[k] = 0, Q.push({ k }), t[k] = k;
                else
                    d[k] = inf;
            
            ll cost = inf;
            int last;

            while (!Q.empty())
            {
                int key = Q.top().key;
                Q.pop();

                if (a[j].f[key] && d[key] < cost)
                    cost = d[key], last = key;

                for (auto& k : g[key])
                    if (d[k.first] > d[key] + k.second)
                    {
                        d[k.first] = d[key] + k.second;
                        t[k.first] = key;

                        Q.push({ k.first });
                    }
            }

            ll newCost = a[i].cost + a[j].cost + cost;

            if (newCost >= a[aux].cost)
                continue;

            a[aux].cost = newCost;
            a[aux].f = (a[i].f | a[j].f);

            while (t[last] != last)
            {
                a[aux].f[last] = true;
                last = t[last];
            }
        }

    cout << a[(1 << sz) - 1].cost;

    return 0;
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:53:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |     for (int i = 0; i < v.size(); i++)
      |                     ~~^~~~~~~~~~
cities.cpp:104:26: warning: 'last' may be used uninitialized in this function [-Wmaybe-uninitialized]
  104 |             while (t[last] != last)
      |                    ~~~~~~^

• Subtask 1: 0 / 22
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 26