Submission #745771

#	Time	Username	Problem	Language	Result	Execution time	Memory
745771		vjudge1	Cities (BOI16_cities)	C++17	22 / 100	195 ms	468 KiB

cities

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

#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define fi first
#define se second

struct edge {
    int from, to, wei;
    bool operator < (const edge &other) const {
        return wei > other.wei;
    }
};

const int maxn = 20;
const int inf = 1e16 + 42;

int n, k, m;
vector<edge> graph[maxn];
bool special[maxn];

int try_for(int mask) {
    vector<bool> vis(n, false);
    int start = -1;
    for(int i = 0; i < n; i++) {
        if(mask & (1 << i)) {
            start = i;
            break;
        }
    }
    priority_queue<edge> q;
    q.push({-1, start, 0});
    int res = 0;
    while(!q.empty()) {
        edge e = q.top();
        q.pop();
        //cout << e.from << " " << e.to << " " << e.wei << "\n";
        if(vis[e.to]) {
            continue;
        }
        vis[e.to] = true;
        res += e.wei;
        for(edge nei : graph[e.to]) {
            //cout << nei.to;
            if(mask & (1 << nei.to)) {
                //cout << " +1";
                if(!vis[nei.to]) {
                    //cout << " +1";
                    q.push(nei);
                }
            }
            //cout << "\n";
        }
    }
    for(int i = 0; i < n; i++) {
        if(mask & (1 << i)) {
            if(!vis[i]) {
                return inf;
            }
        }
    }
    return res;
}

void solve() {
    cin >> n >> k >> m;
    for(int i = 0; i < k; i++) {
        int x;
        cin >> x;
        x--;
        special[x] = true;
    }
    for(int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        a--, b--;
        graph[a].pb({a, b, c});
        graph[b].pb({b, a, c});
    }
    int ans = inf;
    for(int mask = 0; mask < (1 << n); mask++) {
        bool ok = true;
        for(int i = 0; i < n; i++) {
            if(special[i] && ((mask & (1 << i)) == 0)) {
                ok = false;
                break;
            }
        }
        if(!ok) {
            continue;
        }
        int res = try_for(mask);
        if(ans > res) {
            ans = res;
        }
    }
    cout << ans << "\n";
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
    return 0;
}

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