Submission #501054

#	Time	Username	Problem	Language	Result	Execution time	Memory
501054		dxz05	Cities (BOI16_cities)	C++14	14 / 100	315 ms	39572 KiB

cities

#pragma GCC optimize("Ofast,O2,O3,unroll-loops")
#pragma GCC target("avx2")

#include <bits/stdc++.h>

using namespace std;

void debug_out() { cerr << endl; }

template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << "[" << H << "]";
    debug_out(T...);
}

#ifdef dddxxz
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SZ(s) ((int)s.size())
#define all(x) (x).begin(), (x).end()
#define lla(x) (x).rbegin(), (x).rend()

clock_t startTime;

double getCurrentTime() {
    return (double) (clock() - startTime) / CLOCKS_PER_SEC;
}

#define MP make_pair

typedef long long ll;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
const double eps = 0.000001;
const int MOD = 998244353;
const int INF = 1000000101;
const long long LLINF = 1223372000000000555;
const int N = 1e6 + 3e2;
const int M = 222;

vector<pair<int, int>> g[N];

void dijkstra(int root, vector<ll> &d){
    d[root] = 0;
    priority_queue<pair<ll, int>> pq;
    pq.push(MP(0, root));
    vector<bool> processed(d.size(), false);

    while (!pq.empty()){
        int v = pq.top().second; pq.pop();
        if (processed[v]) continue;
        processed[v] = true;
        for (auto e : g[v]){
            int u = e.first, w = e.second;
            if (d[u] > d[v] + w){
                d[u] = d[v] + w;
                pq.push(MP(-d[u], u));
            }
        }
    }

//    for (ll x : d) cout << x << ' '; cout << endl;

}

void solve(int TC) {
    int n, k, m;
    cin >> n >> k >> m;

    vector<int> imp(k);
    for (int &i : imp){
        cin >> i;
        --i;
    }

    for (int i = 0; i < m; i++){
        int u, v, w;
        cin >> u >> v >> w;
        --u, --v;
        g[u].emplace_back(v, w);
        g[v].emplace_back(u, w);
    }

    vector<vector<ll>> d(k, vector<ll>(n, LLINF));
    for (int i = 0; i < k; i++){
        dijkstra(imp[i], d[i]);
    }

    if (k <= 3){
        ll ans = LLINF;
        for (int i = 0; i < n; i++){
            ll cur = 0;
            for (int j = 0; j < k; j++){
                cur += d[j][i];
            }
            ans = min(ans, cur);
        }
        cout << ans;
        return;
    }

}

int main() {
    startTime = clock();
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

#ifdef dddxxz
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int TC = 1;
//    cin >> TC;

    for (int test = 1; test <= TC; test++) {
        //debug(test);
        //cout << "Case #" << test << ": ";
        solve(test);
    }

    cerr << endl << "Time: " << int(getCurrentTime() * 1000) << " ms" << endl;

    return 0;
}

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