Submission #251416

#	Time	Username	Problem	Language	Result	Execution time	Memory
251416		atoiz	Fireworks (APIO16_fireworks)	C++14	0 / 100	9 ms	14464 KiB

fireworks

/*input
4 6
1 5
2 5
2 8
3 3
3 2
3 3
2 9
4 4
4 3
*/

#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cassert>

using namespace std;

#define FOR(i, a, b) for (int i = a; i <= b; ++i)
#define FORA(i, a) for (auto &i : a)
#define FORB(i, a, b) for (int i = a; i >= b; --i)

const int MAXN = 300007;
int P[MAXN], C[MAXN], N, M, D[MAXN], L[MAXN], R[MAXN];
vector<int> events[MAXN];
vector<int> children[MAXN];
long long ans = 0;

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> N >> M;
	FOR(i, 2, N + M) {
		cin >> P[i] >> C[i];
		children[P[i]].push_back(i);
	}

	FOR(i, 1, N) assert(!children[i].empty());
	FOR(i, N + 1, N + M) assert(children[i].empty());

	FOR(i, N + 1, N + M) L[i] = C[i], R[i] = C[i];
	FORB(i, N, 1) {
		vector<int> vec;
		for (int j : children[i]) vec.push_back(L[j] * 2), vec.push_back(R[j] * 2 + 1);
		sort(vec.begin(), vec.end());
		int l = -1, r = -1;
		long long cur = 0, best;
		int last = 0, a = (int) children[i].size();
		for (int j : children[i]) cur += L[j];
		best = cur;

		// cout << i << "= ";
		// for (int x : vec) cout << x << ' '; cout << endl;

		for (auto it = vec.begin(); it != vec.end();) {
			int x = *it;
			cur -= (x / 2 - last) * a, last = x / 2;
			if (cur == best) r = x;
			for (; it != vec.end() && *it == x; ++it) --a;
			if (cur < best) best = cur, l = x, r = x;
		}
		l /= 2, r /= 2;

		for (int j : children[i]) {
			if (l < L[j]) ans += L[j] - l;
			else if (l > R[j]) ans += l - R[j];
			// cout << "+ " << j << ": " << ans << endl;
		}

		L[i] = l + C[i], R[i] = r + C[i];
		// cout << i << ": " << l << ' ' << r << " + " << L[i] << ' ' << R[i] << " - " << ans << endl;
	}

	cout << ans << endl;
}

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