Submission #87683

#	Time	Username	Problem	Language	Result	Execution time	Memory
87683		JustInCase	Bitaro’s Party (JOI18_bitaro)	C++17	7 / 100	2023 ms	15512 KiB

bitaro

#include <bits/stdc++.h>

const int32_t MAX_N = 1e5;
const int32_t BUCKET_SIZE = 200;

bool isForbidden[MAX_N + 5];

class Graph {
private:
	struct Node {
		int32_t id;
		std::vector< std::pair< int32_t, int32_t > > dp;
		std::vector< Node* > v, rev;
	};

	int32_t cntNodes;
	Node nodes[MAX_N + 5];
	
public:
	void Init(int32_t _cntNodes) {
		cntNodes = _cntNodes;

		for(int32_t i = 1; i <= cntNodes; i++) {
			nodes[i].id = i;
		}
	}

	void AddEdge(int32_t from, int32_t to) {
		nodes[from].v.push_back(&nodes[to]);
		nodes[to].rev.push_back(&nodes[from]);
	}

	void Precompute() {
		for(int32_t i = 1; i <= cntNodes; i++) {
			std::vector< std::pair< int32_t, int32_t > > dists;
			
			dists.push_back({ 0, i });
			for(auto &x : nodes[i].v) {
				for(auto &y : x->dp) {
					dists.push_back({ y.first + 1, y.second });
				}
			}

			std::sort(dists.begin(), dists.end());
			
			for(int32_t j = dists.size() - 1; j >= 0; j--) {
				if(nodes[i].dp.size() == 0 || nodes[i].dp.back().second != dists[j].second) {
					nodes[i].dp.push_back(dists[j]);

					if(nodes[i].dp.size() == BUCKET_SIZE) {
						break;
					}
				}
			}
		}
	}

	int32_t SolveSmallK(int32_t t) {
		for(auto &x : nodes[t].dp) {
			if(!isForbidden[x.second]) {
				return x.first;
			}
		}

		return -1;
	}

	int32_t SolveBigK(int32_t t) {
		std::vector< int32_t > dp(t + 1, 0);

		int32_t ans = (isForbidden[t] ? -1 : 0);
		for(int32_t i = t - 1; i >= 1; i--) {
			bool isChanged = false;
			for(auto &x : nodes[i].rev) {
				if(x->id <= t && (x->id == t || dp[x->id] != 0)) {
					dp[i] = std::max(dp[i], dp[x->id] + 1);
					isChanged = true;
				}
			}
			
			if(isChanged && !isForbidden[i]) {
				ans = std::max(ans, dp[i]);
			}
		}

		return ans;
	}	
};

Graph g;

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

	int32_t n, m, q;
	std::cin >> n >> m >> q;

	g.Init(n);
	
	for(int32_t i = 0; i < m; i++) {
		int32_t u, v;
		std::cin >> u >> v;

		g.AddEdge(v, u);
	}
	
	g.Precompute();

	for(int32_t i = 0; i < q; i++) {
		int32_t t, k;
		std::cin >> t >> k;
	
		std::vector< int32_t > c(k);
		for(int32_t j = 0; j < k; j++) {
			std::cin >> c[j];

			isForbidden[c[j]] = true;
		}

		if(k >= BUCKET_SIZE) {
			std::cout << g.SolveBigK(t) << '\n';
		}
		else {
			std::cout << g.SolveSmallK(t) << '\n';
		}

		for(int32_t j = 0; j < k; j++) {
			isForbidden[c[j]] = false;
		}
	}
}

• Subtask 1: 7 / 7
• Subtask 2: 0 / 7
• Subtask 3: 0 / 86