Submission #1158275

#	Time	Username	Problem	Language	Result	Execution time	Memory
1158275		countless	September (APIO24_september)	C++20	0 / 100	0 ms	320 KiB

september

#include "september.h"
#include <bits/stdc++.h>
#include <vector>

using namespace std;

int dfs(int node, vector<vector<int>> &down, vector<bool> &vis) {
	int res = 0;

	for (const auto &child : down[node]) {
		if (!vis[child]) {
			vis[child] = true;
			res++;
			res += dfs(child, down, vis);
		}
	}

	return res;
}

int solve(int N, int M, std::vector<int> F, std::vector<std::vector<int>> S) {
	int ans = 0;
	vector<vector<int>> down(N, vector<int>());
	
	for (int i = 1; i < N; i++) down[F[i]].push_back(i);

	// "compress" the M queries
	vector<int> comp(N, -1);
	for (int m = 0; m < M; m++) {
		for (int j = 0; j < N - 1; j++) {
			comp[S[m][j]] = max(comp[S[m][j]], j);
		}
	}

	int dels = 0;
	int sweep = 0;
	vector<bool> vis(N, false);
	vector<int> cnt(N, 0);

	for (int i = 0; i < N - 1; i++) {
		// delete itself and all its children
		// not including vis'd
		if (!vis[comp[i]]) {
			vis[comp[i]] = true;
			dels++;

			dels += dfs(comp[i], down, vis);
		}

		cerr << dels << endl;

		// increment how many times we've seen this node
		cnt[comp[i]]++;

		// interval start and end
		// first time we've seen it
		if (cnt[comp[i]] == 1) sweep++;
		// last time we've seen it
		if (cnt[comp[i]] == M) sweep--;

		// when an interval "closes," increment ans
		// an interval closes when
		// we've seen all the nodes in the interval
		// specifically, for any node, it's subtree is contained in the interval
		// thus, this is only possible when the amount of deletions
		// is equal to the amount of nodes in the interval
		if (i + 1 == dels && sweep == 0) {
			ans++;
		}
	}

	return ans;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 14
• Subtask 3: 0 / 5
• Subtask 4: 0 / 9
• Subtask 5: 0 / 5
• Subtask 6: 0 / 11
• Subtask 7: 0 / 9
• Subtask 8: 0 / 11
• Subtask 9: 0 / 9
• Subtask 10: 0 / 16