Submission #626737

#	Time	Username	Problem	Language	Result	Execution time	Memory
626737		elalabaj	Fireworks (APIO16_fireworks)	C++17	100 / 100	236 ms	75596 KiB

fireworks

#include <bits/stdc++.h>

typedef long long ll;

struct V {
    ll w = 0;
    std::vector<int> edges;
    ll y0 = 0;
    ll d0 = 0;
    std::priority_queue<ll> points;
};

void solve(ll i, std::vector<V>& graph) {
    V& v = graph[i];
    if (v.edges.empty()) return;

    for (auto j : v.edges) {
        solve(j, graph);
        V& w = graph[j];
        v.y0 += w.y0;
        v.d0 += w.d0;
        if (v.points.size() < w.points.size()) {
            std::swap(v.points, w.points);
        }
        while (!w.points.empty()) {
            v.points.push(w.points.top());
            w.points.pop();
        }
    }

    if (i == 1) return;

    v.y0 += v.w;
    ll pv1 = v.points.top(); v.points.pop();
    ll pv2 = v.points.top(); v.points.pop();

    while (v.d0 + (ll)v.points.size() > -1) {
        pv1 = pv2;
        pv2 = v.points.top();
        v.points.pop();
    }
    v.points.push(pv2 + v.w);
    v.points.push(pv1 + v.w);
}


int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(nullptr);
	std::cout.tie(nullptr);

    ll n, m;
    std::cin >> n >> m;

    std::vector<V> graph(n + m + 1);
    for (ll i = 2; i <= n + m; i++) {
        ll a, b;
        std::cin >> a >> b;
        graph[a].edges.push_back(i);
        graph[i].w = b;
    }

    for (ll i = n + 1; i <= n + m; i++) {
        graph[i].y0 = graph[i].w;
        graph[i].d0 = -1;
        graph[i].points.push(graph[i].w);
        graph[i].points.push(graph[i].w);
    }

    solve(1, graph);

    std::vector<ll> points;
    while (!graph[1].points.empty()) {
        points.push_back(graph[1].points.top());
        graph[1].points.pop();
    }
    std::reverse(points.begin(), points.end());

    ll x = 0;
    ll y = graph[1].y0;
    ll d = graph[1].d0;
    ll min = y;
    for (auto p : points) {
        y += (ll) d * (p - x);
        d++;
        x = p;
        min = std::min(min, y);
    }    

    std::cout << min << '\n';

	return 0;
}

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