Submission #752951

#	Time	Username	Problem	Language	Result	Execution time	Memory
752951		benjaminkleyn	Fireworks (APIO16_fireworks)	C++17	7 / 100	7 ms	7380 KiB

fireworks

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int MAX = 300010;
int n, m;
int p[2 * MAX]; 
ll c[2 * MAX];
vector<pair<int, ll>> g[MAX];

struct state
{
    ll cost, distance, wiggle_room;
};

pair<ll,ll> dp(int u)
{
    if (u > n)
        return {0, 0};

    ll res = 0;
    vector<ll> times;
    ll min_val = 0;
    for (auto [v, l] : g[u])
    {
        auto [t, d] = dp(v);
        res += t;
        times.push_back(l + d);
        min_val = max(min_val, d);
    }
    vector<ll> t = times;
    sort(t.begin(), t.end());

    if (min_val >= t[t.size() / 2])
    {
        ll best = min_val;
        for (ll x : times)
            res += abs(best - x);
        return {res, best};
    }

    ll best = t[(t.size() - 1) / 2];
    for (ll x : times)
        res += abs(best - x);

    return {res, best};
}

int main()
{
    cin.tie(0)->sync_with_stdio(0);

    cin >> n >> m;
    p[1] = -1, c[1] = 0;
    for (int i = 2; i <= n + m; i++)
    {
        cin >> p[i] >> c[i];
        g[p[i]].push_back({i, c[i]});
    }

    cout << dp(1).first << '\n';

    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 0 / 19
• Subtask 3: 0 / 29
• Subtask 4: 0 / 45