Submission #1172396

#	Time	Username	Problem	Language	Result	Execution time	Memory
1172396		VMaksimoski008	Cities (BOI16_cities)	C++20	100 / 100	4844 ms	140872 KiB

cities

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

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,bmi,bmi2,lzcnt,popcnt")

const int maxn = 1e5 + 5;

ll D[5][maxn], dp[1<<5][maxn], imp[5];
bool vis[maxn], vis2[1<<5][maxn];
int n, k, m;
vector<pii> G[maxn];

void dijkstra(int src, ll D[]) {
    priority_queue<pll, vector<pll>, greater<>> pq;
    fill(D, D + n + 1, 1e18);
    fill(vis, vis + n + 1, 0);
    pq.push({ D[src] = 0, src });
    
    while(!pq.empty()) {
        auto [d, u] = pq.top(); pq.pop();
        if(vis[u]) continue;
        vis[u] = 1;
        for(auto [v, w] : G[u])
            if(D[v] > d + w && !vis[v])
                pq.push({ D[v] = d + w, v });
    }
}

signed main() {
    ios_base::sync_with_stdio(false);
    cout.tie(0); cin.tie(0);

    cin >> n >> k >> m;
    for(int i=0; i<k; i++) cin >> imp[i];

    for(int i=1; i<=m; i++) {
        int a, b, w; cin >> a >> b >> w;
        G[a].push_back({ b, w });
        G[b].push_back({ a, w });
    }

    for(int i=0; i<k; i++)
        dijkstra(imp[i], D[i]);

    priority_queue<ar<ll, 3>, vector<ar<ll, 3> >, greater<> > pq;
    for(int i=1; i<=n; i++)
        for(int j=0; j<(1<<k); j++)
            dp[j][i] = 1e18;

    for(int i=0; i<k; i++) {
        dp[1<<i][imp[i]] = 0;
        pq.push({ 0, imp[i], (1<<i) });
    }

    while(!pq.empty()) {
        auto [d, u, s] = pq.top(); pq.pop();
        if (vis2[s][u]) continue;
        vis2[s][u] = 1;

        for(auto [v, w] : G[u])
            if(dp[s][v] > d + w && !vis2[s][v])
                pq.push({dp[s][v] = d + w, v, s});

        for(int i=0; i<k; i++) {
            int ns = s | (1 << i);
            if(dp[ns][u] > d + D[i][u] && !vis2[ns][u])
                pq.push({ dp[ns][u] = d + D[i][u], u, ns });
        }
    }

    ll ans = 5e18;
    for(int i=1; i<=n; i++)
        ans = min(ans, dp[(1<<k)-1][i]);
    cout << ans << '\n';
}

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