oj.uz

Submission #87733

# Submission time Handle Problem Language Result Execution time Memory
87733 2018-12-02T09:02:08 Z JustInCase Bitaro’s Party (JOI18_bitaro) C++17
14 / 100
 2000 ms 419528 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 = 316;

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 8308 KB Output is correct
3 Correct 9 ms 8308 KB Output is correct
4 Correct 9 ms 8464 KB Output is correct
5 Correct 13 ms 8852 KB Output is correct
6 Correct 14 ms 8868 KB Output is correct
7 Correct 13 ms 8868 KB Output is correct
8 Correct 22 ms 11812 KB Output is correct
9 Correct 22 ms 11940 KB Output is correct
10 Correct 22 ms 11940 KB Output is correct
11 Correct 22 ms 11940 KB Output is correct
12 Correct 16 ms 11940 KB Output is correct
13 Correct 21 ms 11940 KB Output is correct
14 Correct 19 ms 11940 KB Output is correct
15 Correct 16 ms 11940 KB Output is correct
16 Correct 19 ms 11940 KB Output is correct
17 Correct 20 ms 11940 KB Output is correct
18 Correct 17 ms 11940 KB Output is correct
19 Correct 20 ms 11940 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 8308 KB Output is correct
3 Correct 9 ms 8308 KB Output is correct
4 Correct 9 ms 8464 KB Output is correct
5 Correct 13 ms 8852 KB Output is correct
6 Correct 14 ms 8868 KB Output is correct
7 Correct 13 ms 8868 KB Output is correct
8 Correct 22 ms 11812 KB Output is correct
9 Correct 22 ms 11940 KB Output is correct
10 Correct 22 ms 11940 KB Output is correct
11 Correct 22 ms 11940 KB Output is correct
12 Correct 16 ms 11940 KB Output is correct
13 Correct 21 ms 11940 KB Output is correct
14 Correct 19 ms 11940 KB Output is correct
15 Correct 16 ms 11940 KB Output is correct
16 Correct 19 ms 11940 KB Output is correct
17 Correct 20 ms 11940 KB Output is correct
18 Correct 17 ms 11940 KB Output is correct
19 Correct 20 ms 11940 KB Output is correct
20 Correct 847 ms 16256 KB Output is correct
21 Correct 759 ms 16264 KB Output is correct
22 Correct 838 ms 16456 KB Output is correct
23 Correct 864 ms 16456 KB Output is correct
24 Correct 1285 ms 260656 KB Output is correct
25 Correct 1336 ms 272188 KB Output is correct
26 Correct 1349 ms 272188 KB Output is correct
27 Correct 1449 ms 419384 KB Output is correct
28 Correct 1448 ms 419384 KB Output is correct
29 Correct 1450 ms 419384 KB Output is correct
30 Correct 1436 ms 419384 KB Output is correct
31 Correct 1629 ms 419384 KB Output is correct
32 Correct 1529 ms 419384 KB Output is correct
33 Correct 1107 ms 419384 KB Output is correct
34 Correct 1081 ms 419384 KB Output is correct
35 Correct 1100 ms 419384 KB Output is correct
36 Correct 1357 ms 419384 KB Output is correct
37 Correct 1387 ms 419384 KB Output is correct
38 Correct 1333 ms 419384 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 8308 KB Output is correct
3 Correct 9 ms 8308 KB Output is correct
4 Correct 9 ms 8464 KB Output is correct
5 Correct 13 ms 8852 KB Output is correct
6 Correct 14 ms 8868 KB Output is correct
7 Correct 13 ms 8868 KB Output is correct
8 Correct 22 ms 11812 KB Output is correct
9 Correct 22 ms 11940 KB Output is correct
10 Correct 22 ms 11940 KB Output is correct
11 Correct 22 ms 11940 KB Output is correct
12 Correct 16 ms 11940 KB Output is correct
13 Correct 21 ms 11940 KB Output is correct
14 Correct 19 ms 11940 KB Output is correct
15 Correct 16 ms 11940 KB Output is correct
16 Correct 19 ms 11940 KB Output is correct
17 Correct 20 ms 11940 KB Output is correct
18 Correct 17 ms 11940 KB Output is correct
19 Correct 20 ms 11940 KB Output is correct
20 Correct 847 ms 16256 KB Output is correct
21 Correct 759 ms 16264 KB Output is correct
22 Correct 838 ms 16456 KB Output is correct
23 Correct 864 ms 16456 KB Output is correct
24 Correct 1285 ms 260656 KB Output is correct
25 Correct 1336 ms 272188 KB Output is correct
26 Correct 1349 ms 272188 KB Output is correct
27 Correct 1449 ms 419384 KB Output is correct
28 Correct 1448 ms 419384 KB Output is correct
29 Correct 1450 ms 419384 KB Output is correct
30 Correct 1436 ms 419384 KB Output is correct
31 Correct 1629 ms 419384 KB Output is correct
32 Correct 1529 ms 419384 KB Output is correct
33 Correct 1107 ms 419384 KB Output is correct
34 Correct 1081 ms 419384 KB Output is correct
35 Correct 1100 ms 419384 KB Output is correct
36 Correct 1357 ms 419384 KB Output is correct
37 Correct 1387 ms 419384 KB Output is correct
38 Correct 1333 ms 419384 KB Output is correct
39 Correct 1613 ms 419384 KB Output is correct
40 Correct 1449 ms 419384 KB Output is correct
41 Correct 1485 ms 419384 KB Output is correct
42 Correct 1844 ms 419384 KB Output is correct
43 Correct 1404 ms 419384 KB Output is correct
44 Correct 876 ms 419384 KB Output is correct
45 Correct 855 ms 419384 KB Output is correct
46 Correct 837 ms 419384 KB Output is correct
47 Correct 904 ms 419384 KB Output is correct
48 Correct 851 ms 419384 KB Output is correct
49 Correct 1737 ms 419424 KB Output is correct
50 Correct 1666 ms 419424 KB Output is correct
51 Correct 800 ms 419424 KB Output is correct
52 Correct 788 ms 419424 KB Output is correct
53 Correct 1650 ms 419424 KB Output is correct
54 Correct 1687 ms 419424 KB Output is correct
55 Correct 1593 ms 419424 KB Output is correct
56 Correct 1510 ms 419424 KB Output is correct
57 Correct 886 ms 419424 KB Output is correct
58 Correct 881 ms 419424 KB Output is correct
59 Correct 826 ms 419424 KB Output is correct
60 Correct 835 ms 419424 KB Output is correct
61 Correct 1786 ms 419424 KB Output is correct
62 Correct 1631 ms 419424 KB Output is correct
63 Correct 1630 ms 419424 KB Output is correct
64 Execution timed out 2062 ms 419528 KB Time limit exceeded
65 Halted 0 ms 0 KB -