Submission #500837

#	Time	Username	Problem	Language	Result	Execution time	Memory
500837		Stickfish	Fireworks (APIO16_fireworks)	C++17	7 / 100	5 ms	7372 KiB

fireworks

#include <iostream>
#include <vector>
using namespace std;
using ll = long long;

struct dpvl {
    ll l;
    ll r;
    ll mn; 

    dpvl() {}

    dpvl(ll l_, ll r_, ll mn_): l(l_), r(r_), mn(mn_) {}

    ll operator()(ll x) {
        if (l <= x && x <= r)
            return mn;
        return min(abs(l - x), abs(r - x)) + mn;
    }
};

const int MAXN = 300003;
const ll INF = 1.77013e9;
vector<pair<int, ll>> edg[MAXN];
pair<int, ll> root[MAXN];

ll lower_bound_dir(vector<dpvl>& v, ll x) {
    ll lb = -INF, ub = INF;
    while (ub - lb > 1) {
        ll mb = (lb + ub) / 2;
        ll ans = 0;
        for (auto d : v) {
            ans += d(mb + 1) - d(mb);
        }
        if (ans < x)
            lb = mb;
        else
            ub = mb;
    }
    return ub;
}

dpvl dfs(int v, int n) {
    if (v >= n) {
        return {root[v].second, root[v].second, 0};
    }
    vector<dpvl> ch;
    for (auto [u, d] : edg[v]) {
        ch.push_back(dfs(u, n));
    }
    ll l = lower_bound_dir(ch, 0);
    ll r = lower_bound_dir(ch, 1);
    ll mn = 0;
    for (auto d : ch)
        mn += d(l);
    return {l + root[v].second, r + root[v].second, mn};
}

signed main() {
    int n, m;
    cin >> n >> m;
    ll addans = 0;
    for (int i = 1; i < n + m; ++i) {
        int u, d;
        cin >> u >> d;
        --u;
        if (u >= n) {
            addans += d;
        } else {
            edg[u].push_back({i, d});
            root[i] = {u, d};
        }
    }
    cout << dfs(0, n).mn << endl;
}

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