Submission #708047

#	Time	Username	Problem	Language	Result	Execution time	Memory
708047		stevancv	Cities (BOI16_cities)	C++14	100 / 100	3151 ms	48724 KiB

cities

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 3e5 + 5;
const ll linf = 1e18;
const int mod = 1e9 + 7;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, k, m;
    cin >> n >> k >> m;
    int K = 1 << k;
    vector<vector<ll>> dp(n, vector<ll>(K, linf));
    vector<int> imp(k);
    for (int i = 0; i < k; i++) {
        cin >> imp[i];
        imp[i] -= 1;
        dp[imp[i]][1 << i] = 0;
    }
    vector<vector<pair<int, int>>> g(n);
    for (int i = 0; i < m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        u -= 1; v -= 1;
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }
    for (int mask = 0; mask < K; mask++) {
        for (int i = 0; i < n; i++) {
            for (int smask = mask; ; smask = (smask - 1) & mask) {
                smin(dp[i][mask], dp[i][smask] + dp[i][mask ^ smask]);
                if (smask == 0) break;
            }
        }
        priority_queue<pair<ll, int>> pq;
        for (int i = 0; i < n; i++) {
            if (dp[i][mask] == linf) continue;
            pq.push({-dp[i][mask], i});
        }
        while (!pq.empty()) {
            ll d = -pq.top().first;
            int u = pq.top().second;
            pq.pop();
            if (d > dp[u][mask]) continue;
            for (auto p : g[u]) {
                ll w = d + p.second;
                if (dp[p.first][mask] > w) {
                    dp[p.first][mask] = w;
                    pq.push({-w, p.first});
                }
            }
        }
    }
    ll ans = linf;
    for (int i = 0; i < n; i++) smin(ans, dp[i][K - 1]);
    cout << ans << en;
    return 0;
}

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