답안 #87726 :: oj.uz

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
87726	2018-12-02T08:30:16 Z	JustInCase	Bitaro’s Party (JOI18_bitaro)	C++17	14 / 100	2000 ms	44116 KB

bitaro

/**
Solution:
	Idea: We can precompute for each node the sqrt(n) furthest nodes with a simple dp. Then for each query
if the number of forbidden nodes is less than sqrt(n) then for sure the answer will be among the precomputed
otherwise we can simply solve it with a brutefore since the queries of this type will be less than sqrt(n).
*/
#include <bits/stdc++.h>

const int32_t MAX_N = 1e5;
const int32_t BUCKET_SIZE = 30;

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
7.0 / 7.0

#	결과	실행 시간	메모리	Grader output
1	Correct	9 ms	8156 KB	Output is correct
2	Correct	11 ms	8316 KB	Output is correct
3	Correct	10 ms	8364 KB	Output is correct
4	Correct	10 ms	8364 KB	Output is correct
5	Correct	15 ms	8556 KB	Output is correct
6	Correct	15 ms	8568 KB	Output is correct
7	Correct	16 ms	8600 KB	Output is correct
8	Correct	14 ms	8896 KB	Output is correct
9	Correct	16 ms	8904 KB	Output is correct
10	Correct	15 ms	8904 KB	Output is correct
11	Correct	13 ms	8904 KB	Output is correct
12	Correct	15 ms	8904 KB	Output is correct
13	Correct	13 ms	8904 KB	Output is correct
14	Correct	12 ms	8904 KB	Output is correct
15	Correct	12 ms	8904 KB	Output is correct
16	Correct	16 ms	8904 KB	Output is correct
17	Correct	13 ms	8904 KB	Output is correct
18	Correct	14 ms	8904 KB	Output is correct
19	Correct	13 ms	8904 KB	Output is correct

Subtask #2
7.0 / 7.0

#	결과	실행 시간	메모리	Grader output
1	Correct	9 ms	8156 KB	Output is correct
2	Correct	11 ms	8316 KB	Output is correct
3	Correct	10 ms	8364 KB	Output is correct
4	Correct	10 ms	8364 KB	Output is correct
5	Correct	15 ms	8556 KB	Output is correct
6	Correct	15 ms	8568 KB	Output is correct
7	Correct	16 ms	8600 KB	Output is correct
8	Correct	14 ms	8896 KB	Output is correct
9	Correct	16 ms	8904 KB	Output is correct
10	Correct	15 ms	8904 KB	Output is correct
11	Correct	13 ms	8904 KB	Output is correct
12	Correct	15 ms	8904 KB	Output is correct
13	Correct	13 ms	8904 KB	Output is correct
14	Correct	12 ms	8904 KB	Output is correct
15	Correct	12 ms	8904 KB	Output is correct
16	Correct	16 ms	8904 KB	Output is correct
17	Correct	13 ms	8904 KB	Output is correct
18	Correct	14 ms	8904 KB	Output is correct
19	Correct	13 ms	8904 KB	Output is correct
20	Correct	546 ms	13540 KB	Output is correct
21	Correct	489 ms	13540 KB	Output is correct
22	Correct	499 ms	13540 KB	Output is correct
23	Correct	501 ms	13688 KB	Output is correct
24	Correct	619 ms	37500 KB	Output is correct
25	Correct	650 ms	37500 KB	Output is correct
26	Correct	660 ms	37500 KB	Output is correct
27	Correct	577 ms	43940 KB	Output is correct
28	Correct	593 ms	44100 KB	Output is correct
29	Correct	483 ms	44116 KB	Output is correct
30	Correct	465 ms	44116 KB	Output is correct
31	Correct	517 ms	44116 KB	Output is correct
32	Correct	482 ms	44116 KB	Output is correct
33	Correct	448 ms	44116 KB	Output is correct
34	Correct	444 ms	44116 KB	Output is correct
35	Correct	473 ms	44116 KB	Output is correct
36	Correct	562 ms	44116 KB	Output is correct
37	Correct	601 ms	44116 KB	Output is correct
38	Correct	567 ms	44116 KB	Output is correct

Subtask #3
0 / 86.0

#	결과	실행 시간	메모리	Grader output
1	Correct	9 ms	8156 KB	Output is correct
2	Correct	11 ms	8316 KB	Output is correct
3	Correct	10 ms	8364 KB	Output is correct
4	Correct	10 ms	8364 KB	Output is correct
5	Correct	15 ms	8556 KB	Output is correct
6	Correct	15 ms	8568 KB	Output is correct
7	Correct	16 ms	8600 KB	Output is correct
8	Correct	14 ms	8896 KB	Output is correct
9	Correct	16 ms	8904 KB	Output is correct
10	Correct	15 ms	8904 KB	Output is correct
11	Correct	13 ms	8904 KB	Output is correct
12	Correct	15 ms	8904 KB	Output is correct
13	Correct	13 ms	8904 KB	Output is correct
14	Correct	12 ms	8904 KB	Output is correct
15	Correct	12 ms	8904 KB	Output is correct
16	Correct	16 ms	8904 KB	Output is correct
17	Correct	13 ms	8904 KB	Output is correct
18	Correct	14 ms	8904 KB	Output is correct
19	Correct	13 ms	8904 KB	Output is correct
20	Correct	546 ms	13540 KB	Output is correct
21	Correct	489 ms	13540 KB	Output is correct
22	Correct	499 ms	13540 KB	Output is correct
23	Correct	501 ms	13688 KB	Output is correct
24	Correct	619 ms	37500 KB	Output is correct
25	Correct	650 ms	37500 KB	Output is correct
26	Correct	660 ms	37500 KB	Output is correct
27	Correct	577 ms	43940 KB	Output is correct
28	Correct	593 ms	44100 KB	Output is correct
29	Correct	483 ms	44116 KB	Output is correct
30	Correct	465 ms	44116 KB	Output is correct
31	Correct	517 ms	44116 KB	Output is correct
32	Correct	482 ms	44116 KB	Output is correct
33	Correct	448 ms	44116 KB	Output is correct
34	Correct	444 ms	44116 KB	Output is correct
35	Correct	473 ms	44116 KB	Output is correct
36	Correct	562 ms	44116 KB	Output is correct
37	Correct	601 ms	44116 KB	Output is correct
38	Correct	567 ms	44116 KB	Output is correct
39	Correct	775 ms	44116 KB	Output is correct
40	Correct	679 ms	44116 KB	Output is correct
41	Execution timed out	2037 ms	44116 KB	Time limit exceeded
42	Halted	0 ms	0 KB	-

답안 #87726

Compilation message

Subtask #1 7.0 / 7.0

Subtask #2 7.0 / 7.0

Subtask #3 0 / 86.0

Subtask #1
7.0 / 7.0

Subtask #2
7.0 / 7.0

Subtask #3
0 / 86.0