oj.uz

Submission #87735

# Submission time Handle Problem Language Result Execution time Memory
87735 2018-12-02T09:03:52 Z JustInCase Bitaro’s Party (JOI18_bitaro) C++17
14 / 100
 2000 ms 219564 KB 
/**
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 = 200;

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

# Verdict Execution time Memory Grader output
1 Correct 9 ms 8184 KB Output is correct
2 Correct 9 ms 8188 KB Output is correct
3 Correct 9 ms 8264 KB Output is correct
4 Correct 9 ms 8280 KB Output is correct
5 Correct 14 ms 8792 KB Output is correct
6 Correct 17 ms 8808 KB Output is correct
7 Correct 13 ms 8980 KB Output is correct
8 Correct 20 ms 10400 KB Output is correct
9 Correct 20 ms 10400 KB Output is correct
10 Correct 18 ms 10400 KB Output is correct
11 Correct 18 ms 10400 KB Output is correct
12 Correct 15 ms 10400 KB Output is correct
13 Correct 18 ms 10400 KB Output is correct
14 Correct 16 ms 10400 KB Output is correct
15 Correct 18 ms 10400 KB Output is correct
16 Correct 17 ms 10400 KB Output is correct
17 Correct 19 ms 10400 KB Output is correct
18 Correct 9 ms 10400 KB Output is correct
19 Correct 17 ms 10400 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 8184 KB Output is correct
2 Correct 9 ms 8188 KB Output is correct
3 Correct 9 ms 8264 KB Output is correct
4 Correct 9 ms 8280 KB Output is correct
5 Correct 14 ms 8792 KB Output is correct
6 Correct 17 ms 8808 KB Output is correct
7 Correct 13 ms 8980 KB Output is correct
8 Correct 20 ms 10400 KB Output is correct
9 Correct 20 ms 10400 KB Output is correct
10 Correct 18 ms 10400 KB Output is correct
11 Correct 18 ms 10400 KB Output is correct
12 Correct 15 ms 10400 KB Output is correct
13 Correct 18 ms 10400 KB Output is correct
14 Correct 16 ms 10400 KB Output is correct
15 Correct 18 ms 10400 KB Output is correct
16 Correct 17 ms 10400 KB Output is correct
17 Correct 19 ms 10400 KB Output is correct
18 Correct 9 ms 10400 KB Output is correct
19 Correct 17 ms 10400 KB Output is correct
20 Correct 568 ms 14720 KB Output is correct
21 Correct 546 ms 14972 KB Output is correct
22 Correct 603 ms 14972 KB Output is correct
23 Correct 580 ms 14972 KB Output is correct
24 Correct 1041 ms 157856 KB Output is correct
25 Correct 1054 ms 162272 KB Output is correct
26 Correct 1008 ms 162520 KB Output is correct
27 Correct 1027 ms 219364 KB Output is correct
28 Correct 1174 ms 219440 KB Output is correct
29 Correct 1108 ms 219472 KB Output is correct
30 Correct 1147 ms 219472 KB Output is correct
31 Correct 1182 ms 219472 KB Output is correct
32 Correct 1130 ms 219472 KB Output is correct
33 Correct 904 ms 219472 KB Output is correct
34 Correct 867 ms 219472 KB Output is correct
35 Correct 872 ms 219472 KB Output is correct
36 Correct 1042 ms 219472 KB Output is correct
37 Correct 1067 ms 219472 KB Output is correct
38 Correct 1051 ms 219472 KB Output is correct

Subtask #3
0 / 86.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 8184 KB Output is correct
2 Correct 9 ms 8188 KB Output is correct
3 Correct 9 ms 8264 KB Output is correct
4 Correct 9 ms 8280 KB Output is correct
5 Correct 14 ms 8792 KB Output is correct
6 Correct 17 ms 8808 KB Output is correct
7 Correct 13 ms 8980 KB Output is correct
8 Correct 20 ms 10400 KB Output is correct
9 Correct 20 ms 10400 KB Output is correct
10 Correct 18 ms 10400 KB Output is correct
11 Correct 18 ms 10400 KB Output is correct
12 Correct 15 ms 10400 KB Output is correct
13 Correct 18 ms 10400 KB Output is correct
14 Correct 16 ms 10400 KB Output is correct
15 Correct 18 ms 10400 KB Output is correct
16 Correct 17 ms 10400 KB Output is correct
17 Correct 19 ms 10400 KB Output is correct
18 Correct 9 ms 10400 KB Output is correct
19 Correct 17 ms 10400 KB Output is correct
20 Correct 568 ms 14720 KB Output is correct
21 Correct 546 ms 14972 KB Output is correct
22 Correct 603 ms 14972 KB Output is correct
23 Correct 580 ms 14972 KB Output is correct
24 Correct 1041 ms 157856 KB Output is correct
25 Correct 1054 ms 162272 KB Output is correct
26 Correct 1008 ms 162520 KB Output is correct
27 Correct 1027 ms 219364 KB Output is correct
28 Correct 1174 ms 219440 KB Output is correct
29 Correct 1108 ms 219472 KB Output is correct
30 Correct 1147 ms 219472 KB Output is correct
31 Correct 1182 ms 219472 KB Output is correct
32 Correct 1130 ms 219472 KB Output is correct
33 Correct 904 ms 219472 KB Output is correct
34 Correct 867 ms 219472 KB Output is correct
35 Correct 872 ms 219472 KB Output is correct
36 Correct 1042 ms 219472 KB Output is correct
37 Correct 1067 ms 219472 KB Output is correct
38 Correct 1051 ms 219472 KB Output is correct
39 Correct 1247 ms 219472 KB Output is correct
40 Correct 1187 ms 219472 KB Output is correct
41 Correct 1127 ms 219472 KB Output is correct
42 Correct 1542 ms 219472 KB Output is correct
43 Correct 1081 ms 219472 KB Output is correct
44 Correct 620 ms 219472 KB Output is correct
45 Correct 604 ms 219472 KB Output is correct
46 Correct 620 ms 219472 KB Output is correct
47 Correct 686 ms 219472 KB Output is correct
48 Correct 614 ms 219472 KB Output is correct
49 Correct 1293 ms 219508 KB Output is correct
50 Correct 1236 ms 219508 KB Output is correct
51 Correct 606 ms 219508 KB Output is correct
52 Correct 611 ms 219508 KB Output is correct
53 Correct 1290 ms 219508 KB Output is correct
54 Correct 1280 ms 219508 KB Output is correct
55 Correct 1184 ms 219508 KB Output is correct
56 Correct 1216 ms 219508 KB Output is correct
57 Correct 632 ms 219508 KB Output is correct
58 Correct 635 ms 219508 KB Output is correct
59 Correct 580 ms 219508 KB Output is correct
60 Correct 590 ms 219508 KB Output is correct
61 Correct 1642 ms 219508 KB Output is correct
62 Correct 1452 ms 219508 KB Output is correct
63 Correct 1339 ms 219508 KB Output is correct
64 Execution timed out 2070 ms 219564 KB Time limit exceeded
65 Halted 0 ms 0 KB -