Submission #869842

#	Time	Username	Problem	Language	Result	Execution time	Memory
869842		DylanSmith	Fireworks (APIO16_fireworks)	C++17	100 / 100	145 ms	45208 KiB

fireworks

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define pb push_back
#define sz(x) (int)x.size()
#define all(x) begin(x),end(x)
#define lb(x,y) lower_bound(all(x),y)-begin(x)

mt19937 rng;

void solve() {
    int N, M; cin >> N >> M;
    vector<vector<int>> adj(N);
    vector<int> len(N + M, 0);
    for (int i = 1; i < N + M; i++) {
        int u; cin >> u; u--;
        adj[u].pb(i);
        cin >> len[i];
    }
    if (M == 0) {
        cout << 0 << "\n";
        return;
    }
    vector<priority_queue<ll>> x(N + M);
    vector<ll> y(N + M, 0);
    vector<ll> d(N + M, 0);
    for (int u = N + M - 1; u >= 0; u--) {
        if (u >= N) {
            x[u].push(len[u]);
            x[u].push(len[u]);
            d[u] = 1;
        } else {
            for (int v : adj[u]) {
                if (sz(x[v]) > sz(x[u])) {
                    swap(x[u], x[v]);
                    swap(y[u], y[v]);
                    swap(d[u], d[v]);
                }
            }
            int slope = 1;
            for (int v : adj[u]) {
                if (x[v].empty()) continue;
                if (x[v].top() > x[u].top()) {
                    y[u] += y[v] + d[u] * (x[v].top() - x[u].top());
                } else {
                    y[u] += y[v] + d[v] * (x[u].top() - x[v].top());
                }
                while (!x[v].empty()) {
                    x[u].push(x[v].top());
                    x[v].pop();
                }
                d[u] += d[v];
            }
            while (d[u] > 1) {
                d[u]--;
                ll n = x[u].top(); x[u].pop();
                y[u] -= d[u] * (n - x[u].top());
            }
            ll n2 = x[u].top(); x[u].pop();
            ll n1 = x[u].top(); x[u].pop();
            n1 += len[u];
            n2 += len[u];
            x[u].push(n1);
            x[u].push(n2);
        }
    }
    cout << y[0] << "\n";
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    rng = mt19937(chrono::steady_clock::now().time_since_epoch().count());

    solve();

    return 0;
}

Compilation message (stderr)

fireworks.cpp: In function 'void solve()':
fireworks.cpp:43:17: warning: unused variable 'slope' [-Wunused-variable]
   43 |             int slope = 1;
      |                 ^~~~~

• Subtask 1: 7 / 7
• Subtask 2: 19 / 19
• Subtask 3: 29 / 29
• Subtask 4: 45 / 45