답안 #87737 :: oj.uz

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
87737	2018-12-02T09:05:53 Z	JustInCase	Bitaro’s Party (JOI18_bitaro)	C++17	14 / 100	2000 ms	119304 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 = 100;

bool isInVector[MAX_N + 5];
bool isForbidden[MAX_N + 5];

std::vector< std::pair< int32_t, int32_t > > Merge(const std::vector< std::pair< int32_t, int32_t> > &v1, 
		const std::vector< std::pair< int32_t, int32_t > > &v2) {
	std::vector< std::pair< int32_t, int32_t > > ans;

	int32_t ind1 = 0, ind2 = 0;
	while((ind1 < v1.size() || ind2 < v2.size()) && ans.size() < BUCKET_SIZE) {
		if(ind1 < v1.size()) {
			if(ind2 < v2.size()) {
				if(v1[ind1].first >= v2[ind2].first) {
					if(!isInVector[v1[ind1].second]) {
						isInVector[v1[ind1].second] = true;
						ans.push_back(v1[ind1]);
					}
					ind1++;
				}
				else {
					if(!isInVector[v2[ind2].second]) {
						isInVector[v2[ind2].second] = true;
						ans.push_back(v2[ind2]);
					}
					ind2++;
				}
			}
			else {
				if(!isInVector[v1[ind1].second]) {
					isInVector[v1[ind1].second] = true;
					ans.push_back(v1[ind1]);
				}
				ind1++;
			}
		}
		else {
			if(!isInVector[v2[ind2].second]) {
				isInVector[v2[ind2].second] = true;
				ans.push_back(v2[ind2]);
			}
			ind2++;
		}
	}

	for(auto &x : ans) {
		isInVector[x.second] = false;
	}

	return ans;
}

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;
			
			nodes[i].dp.push_back({ 0, i });
			for(auto &x : nodes[i].v) {
				auto aux = x->dp;
				for(auto &y : aux) {
					y.first++;
				}
				nodes[i].dp = Merge(nodes[i].dp, aux);
			}
		}
	}

	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;
		}
	}
}

Compilation message

bitaro.cpp: In function 'std::vector<std::pair<int, int> > Merge(const std::vector<std::pair<int, int> >&, const std::vector<std::pair<int, int> >&)':
bitaro.cpp:20:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while((ind1 < v1.size() || ind2 < v2.size()) && ans.size() < BUCKET_SIZE) {
         ~~~~~^~~~~~~~~~~
bitaro.cpp:20:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while((ind1 < v1.size() || ind2 < v2.size()) && ans.size() < BUCKET_SIZE) {
                             ~~~~~^~~~~~~~~~~
bitaro.cpp:21:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(ind1 < v1.size()) {
      ~~~~~^~~~~~~~~~~
bitaro.cpp:22:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if(ind2 < v2.size()) {
       ~~~~~^~~~~~~~~~~

Subtask #1
7.0 / 7.0

#	결과	실행 시간	메모리	Grader output
1	Correct	11 ms	8184 KB	Output is correct
2	Correct	11 ms	8308 KB	Output is correct
3	Correct	8 ms	8308 KB	Output is correct
4	Correct	10 ms	8460 KB	Output is correct
5	Correct	15 ms	8988 KB	Output is correct
6	Correct	15 ms	8988 KB	Output is correct
7	Correct	15 ms	8988 KB	Output is correct
8	Correct	16 ms	9432 KB	Output is correct
9	Correct	16 ms	9452 KB	Output is correct
10	Correct	16 ms	9452 KB	Output is correct
11	Correct	16 ms	9452 KB	Output is correct
12	Correct	16 ms	9452 KB	Output is correct
13	Correct	17 ms	9724 KB	Output is correct
14	Correct	16 ms	9724 KB	Output is correct
15	Correct	14 ms	9724 KB	Output is correct
16	Correct	14 ms	9724 KB	Output is correct
17	Correct	14 ms	9724 KB	Output is correct
18	Correct	15 ms	9724 KB	Output is correct
19	Correct	14 ms	9724 KB	Output is correct

Subtask #2
7.0 / 7.0

#	결과	실행 시간	메모리	Grader output
1	Correct	11 ms	8184 KB	Output is correct
2	Correct	11 ms	8308 KB	Output is correct
3	Correct	8 ms	8308 KB	Output is correct
4	Correct	10 ms	8460 KB	Output is correct
5	Correct	15 ms	8988 KB	Output is correct
6	Correct	15 ms	8988 KB	Output is correct
7	Correct	15 ms	8988 KB	Output is correct
8	Correct	16 ms	9432 KB	Output is correct
9	Correct	16 ms	9452 KB	Output is correct
10	Correct	16 ms	9452 KB	Output is correct
11	Correct	16 ms	9452 KB	Output is correct
12	Correct	16 ms	9452 KB	Output is correct
13	Correct	17 ms	9724 KB	Output is correct
14	Correct	16 ms	9724 KB	Output is correct
15	Correct	14 ms	9724 KB	Output is correct
16	Correct	14 ms	9724 KB	Output is correct
17	Correct	14 ms	9724 KB	Output is correct
18	Correct	15 ms	9724 KB	Output is correct
19	Correct	14 ms	9724 KB	Output is correct
20	Correct	376 ms	13824 KB	Output is correct
21	Correct	356 ms	13844 KB	Output is correct
22	Correct	371 ms	13868 KB	Output is correct
23	Correct	377 ms	13872 KB	Output is correct
24	Correct	752 ms	93324 KB	Output is correct
25	Correct	756 ms	94460 KB	Output is correct
26	Correct	752 ms	94460 KB	Output is correct
27	Correct	837 ms	119244 KB	Output is correct
28	Correct	847 ms	119304 KB	Output is correct
29	Correct	818 ms	119304 KB	Output is correct
30	Correct	807 ms	119304 KB	Output is correct
31	Correct	794 ms	119304 KB	Output is correct
32	Correct	752 ms	119304 KB	Output is correct
33	Correct	610 ms	119304 KB	Output is correct
34	Correct	587 ms	119304 KB	Output is correct
35	Correct	664 ms	119304 KB	Output is correct
36	Correct	712 ms	119304 KB	Output is correct
37	Correct	652 ms	119304 KB	Output is correct
38	Correct	709 ms	119304 KB	Output is correct

Subtask #3
0 / 86.0

#	결과	실행 시간	메모리	Grader output
1	Correct	11 ms	8184 KB	Output is correct
2	Correct	11 ms	8308 KB	Output is correct
3	Correct	8 ms	8308 KB	Output is correct
4	Correct	10 ms	8460 KB	Output is correct
5	Correct	15 ms	8988 KB	Output is correct
6	Correct	15 ms	8988 KB	Output is correct
7	Correct	15 ms	8988 KB	Output is correct
8	Correct	16 ms	9432 KB	Output is correct
9	Correct	16 ms	9452 KB	Output is correct
10	Correct	16 ms	9452 KB	Output is correct
11	Correct	16 ms	9452 KB	Output is correct
12	Correct	16 ms	9452 KB	Output is correct
13	Correct	17 ms	9724 KB	Output is correct
14	Correct	16 ms	9724 KB	Output is correct
15	Correct	14 ms	9724 KB	Output is correct
16	Correct	14 ms	9724 KB	Output is correct
17	Correct	14 ms	9724 KB	Output is correct
18	Correct	15 ms	9724 KB	Output is correct
19	Correct	14 ms	9724 KB	Output is correct
20	Correct	376 ms	13824 KB	Output is correct
21	Correct	356 ms	13844 KB	Output is correct
22	Correct	371 ms	13868 KB	Output is correct
23	Correct	377 ms	13872 KB	Output is correct
24	Correct	752 ms	93324 KB	Output is correct
25	Correct	756 ms	94460 KB	Output is correct
26	Correct	752 ms	94460 KB	Output is correct
27	Correct	837 ms	119244 KB	Output is correct
28	Correct	847 ms	119304 KB	Output is correct
29	Correct	818 ms	119304 KB	Output is correct
30	Correct	807 ms	119304 KB	Output is correct
31	Correct	794 ms	119304 KB	Output is correct
32	Correct	752 ms	119304 KB	Output is correct
33	Correct	610 ms	119304 KB	Output is correct
34	Correct	587 ms	119304 KB	Output is correct
35	Correct	664 ms	119304 KB	Output is correct
36	Correct	712 ms	119304 KB	Output is correct
37	Correct	652 ms	119304 KB	Output is correct
38	Correct	709 ms	119304 KB	Output is correct
39	Correct	983 ms	119304 KB	Output is correct
40	Correct	932 ms	119304 KB	Output is correct
41	Execution timed out	2017 ms	119304 KB	Time limit exceeded
42	Halted	0 ms	0 KB	-

답안 #87737

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