oj.uz

Submission #87742

# Submission time Handle Problem Language Result Execution time Memory
87742 2018-12-02T09:09:52 Z JustInCase Bitaro’s Party (JOI18_bitaro) C++17
14 / 100
 2000 ms 419540 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 = 320;

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 11 ms 8184 KB Output is correct
2 Correct 11 ms 8364 KB Output is correct
3 Correct 9 ms 8364 KB Output is correct
4 Correct 10 ms 8364 KB Output is correct
5 Correct 15 ms 8920 KB Output is correct
6 Correct 13 ms 8920 KB Output is correct
7 Correct 13 ms 8920 KB Output is correct
8 Correct 22 ms 11836 KB Output is correct
9 Correct 22 ms 11968 KB Output is correct
10 Correct 20 ms 11968 KB Output is correct
11 Correct 23 ms 11968 KB Output is correct
12 Correct 17 ms 11968 KB Output is correct
13 Correct 25 ms 11968 KB Output is correct
14 Correct 21 ms 11968 KB Output is correct
15 Correct 17 ms 11968 KB Output is correct
16 Correct 21 ms 11968 KB Output is correct
17 Correct 20 ms 11968 KB Output is correct
18 Correct 18 ms 11968 KB Output is correct
19 Correct 19 ms 11968 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 8184 KB Output is correct
2 Correct 11 ms 8364 KB Output is correct
3 Correct 9 ms 8364 KB Output is correct
4 Correct 10 ms 8364 KB Output is correct
5 Correct 15 ms 8920 KB Output is correct
6 Correct 13 ms 8920 KB Output is correct
7 Correct 13 ms 8920 KB Output is correct
8 Correct 22 ms 11836 KB Output is correct
9 Correct 22 ms 11968 KB Output is correct
10 Correct 20 ms 11968 KB Output is correct
11 Correct 23 ms 11968 KB Output is correct
12 Correct 17 ms 11968 KB Output is correct
13 Correct 25 ms 11968 KB Output is correct
14 Correct 21 ms 11968 KB Output is correct
15 Correct 17 ms 11968 KB Output is correct
16 Correct 21 ms 11968 KB Output is correct
17 Correct 20 ms 11968 KB Output is correct
18 Correct 18 ms 11968 KB Output is correct
19 Correct 19 ms 11968 KB Output is correct
20 Correct 843 ms 16360 KB Output is correct
21 Correct 751 ms 16360 KB Output is correct
22 Correct 850 ms 16388 KB Output is correct
23 Correct 888 ms 16388 KB Output is correct
24 Correct 1491 ms 260860 KB Output is correct
25 Correct 1423 ms 272232 KB Output is correct
26 Correct 1383 ms 272232 KB Output is correct
27 Correct 1455 ms 419152 KB Output is correct
28 Correct 1492 ms 419280 KB Output is correct
29 Correct 1567 ms 419452 KB Output is correct
30 Correct 1592 ms 419452 KB Output is correct
31 Correct 1584 ms 419452 KB Output is correct
32 Correct 1423 ms 419452 KB Output is correct
33 Correct 1114 ms 419452 KB Output is correct
34 Correct 1028 ms 419452 KB Output is correct
35 Correct 1090 ms 419452 KB Output is correct
36 Correct 1316 ms 419452 KB Output is correct
37 Correct 1323 ms 419452 KB Output is correct
38 Correct 1352 ms 419452 KB Output is correct

Subtask #3
0 / 86.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 8184 KB Output is correct
2 Correct 11 ms 8364 KB Output is correct
3 Correct 9 ms 8364 KB Output is correct
4 Correct 10 ms 8364 KB Output is correct
5 Correct 15 ms 8920 KB Output is correct
6 Correct 13 ms 8920 KB Output is correct
7 Correct 13 ms 8920 KB Output is correct
8 Correct 22 ms 11836 KB Output is correct
9 Correct 22 ms 11968 KB Output is correct
10 Correct 20 ms 11968 KB Output is correct
11 Correct 23 ms 11968 KB Output is correct
12 Correct 17 ms 11968 KB Output is correct
13 Correct 25 ms 11968 KB Output is correct
14 Correct 21 ms 11968 KB Output is correct
15 Correct 17 ms 11968 KB Output is correct
16 Correct 21 ms 11968 KB Output is correct
17 Correct 20 ms 11968 KB Output is correct
18 Correct 18 ms 11968 KB Output is correct
19 Correct 19 ms 11968 KB Output is correct
20 Correct 843 ms 16360 KB Output is correct
21 Correct 751 ms 16360 KB Output is correct
22 Correct 850 ms 16388 KB Output is correct
23 Correct 888 ms 16388 KB Output is correct
24 Correct 1491 ms 260860 KB Output is correct
25 Correct 1423 ms 272232 KB Output is correct
26 Correct 1383 ms 272232 KB Output is correct
27 Correct 1455 ms 419152 KB Output is correct
28 Correct 1492 ms 419280 KB Output is correct
29 Correct 1567 ms 419452 KB Output is correct
30 Correct 1592 ms 419452 KB Output is correct
31 Correct 1584 ms 419452 KB Output is correct
32 Correct 1423 ms 419452 KB Output is correct
33 Correct 1114 ms 419452 KB Output is correct
34 Correct 1028 ms 419452 KB Output is correct
35 Correct 1090 ms 419452 KB Output is correct
36 Correct 1316 ms 419452 KB Output is correct
37 Correct 1323 ms 419452 KB Output is correct
38 Correct 1352 ms 419452 KB Output is correct
39 Correct 1751 ms 419452 KB Output is correct
40 Correct 1608 ms 419452 KB Output is correct
41 Correct 1520 ms 419452 KB Output is correct
42 Correct 1954 ms 419452 KB Output is correct
43 Correct 1493 ms 419452 KB Output is correct
44 Correct 922 ms 419452 KB Output is correct
45 Correct 899 ms 419452 KB Output is correct
46 Correct 875 ms 419452 KB Output is correct
47 Correct 962 ms 419452 KB Output is correct
48 Correct 888 ms 419452 KB Output is correct
49 Correct 1937 ms 419488 KB Output is correct
50 Correct 1837 ms 419488 KB Output is correct
51 Correct 814 ms 419488 KB Output is correct
52 Correct 816 ms 419488 KB Output is correct
53 Correct 1736 ms 419488 KB Output is correct
54 Correct 1506 ms 419488 KB Output is correct
55 Correct 1641 ms 419488 KB Output is correct
56 Correct 1693 ms 419488 KB Output is correct
57 Correct 901 ms 419488 KB Output is correct
58 Correct 907 ms 419488 KB Output is correct
59 Correct 843 ms 419488 KB Output is correct
60 Correct 839 ms 419488 KB Output is correct
61 Correct 1683 ms 419488 KB Output is correct
62 Correct 1688 ms 419488 KB Output is correct
63 Correct 1677 ms 419488 KB Output is correct
64 Execution timed out 2066 ms 419540 KB Time limit exceeded
65 Halted 0 ms 0 KB -