Submission #298856

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
298856	2020-09-14T08:20:15 Z	user202729	Werewolf (IOI18_werewolf)	C++17	100 / 100	1367 ms	124584 KB

werewolf

// moreflags=grader.cpp

#include "werewolf.h"
#include<vector>
#include<set>
#include<climits>
#include<algorithm>
#if not LOCAL
#define NDEBUG
#endif
#include<cassert>

struct Dsu{ // with path compression but without union by rank
	std::vector<int> data; // positive: parent, negative: ~(minimum in component)
	Dsu(int number): data(number){
		for(int node=0; node<number; ++node)
			data[node]=~ node;
	}
	int root(int node){return data[node]>=0 ? data[node]=root(data[node]): node;}
	int minimumInComponent(int node){
		return ~data[root(node)];
	}
	bool join(int first, int sec){
		first=root(first); sec=root(sec);
		if(first==sec) return false;
		data[first]=std::max(data[first], data[sec]); // inverted
		data[sec]=first;
		return true;
	}
};

std::vector<int> check_validity(int N, std::vector<int> X, std::vector<int> Y,
                                std::vector<int> S, std::vector<int> E,
                                std::vector<int> L, std::vector<int> R) {
	std::vector<std::vector<int>> greaterAdd(N), lessAdd(N);
	for(int index=0; index<(int)X.size(); ++index){
		auto const [a, b]=std::minmax({X[index], Y[index]});
		assert(a!=b);
		greaterAdd[a].push_back(b);
		lessAdd[N-1-b].push_back(N-1-a);
	}

	auto const process=[&](std::vector<std::vector<int>>& add)->std::vector<int>{
		// add: adjacency list (elements of list [i] must be strictly greater than i)
		// also reuse add for the children of the resulting par
		// (node n is for -1)
		std::vector<int> par(add.size(), -1);
		Dsu dsu((int)add.size());
		for(auto index=(int)add.size(); index--;){
			for(auto other: add[index]){
				other=dsu.minimumInComponent(other);
				if(other>index){
					auto const success=dsu.join(index, other);
					assert(success);
					assert(par[other]==-1);
					par[other]=index;
				}else assert(other==index);
			}
		}

		for(auto& it: add) it.clear();
		add.emplace_back();
		for(int node=0; node<(int)par.size(); ++node){
			(par[node]<0 ? add.back(): add[par[node]]).push_back(node);
		}

		return par;
	};

	std::vector<int> greaterPar=process(greaterAdd);
	std::vector<int> lessPar=process(lessAdd);
	// greaterPar: the equivalent structure of traversing with the additional condition (vertex >= L)
	// for some L
	// ( i -> greaterPar[i] ) where greaterPar[i]<i

	// lessPar: vice versa, but with flipped vertex indices

	struct Jump{
		std::vector<std::vector<int>> data;
		// assumes -1 is the virtual root
		Jump(std::vector<int> value): data{std::move(value)}{
			for(int step=1; step<(int)data.back().size(); step<<=1){
				std::vector<int> const& a=data.back();
				auto b=a;
				bool useful=false;
				for(auto& it: b) if(it>=0){
					it=a[it];
					if(it>=0) useful=true;
				}
				if(useful)
					data.push_back(std::move(b));
				else break;
			}
		}
		int get(int node, int least)const{
			// assumes par[node]<node for all node, find minimum ancestor >=least
			for(auto layer=data.size(); layer--;)
				if(data[layer][node]>=least) node=data[layer][node];
			return node;
		}
	};
	Jump greaterJump(std::move(greaterPar)), lessJump(std::move(lessPar));

	struct Query{int node, index;};
	std::vector<std::vector<Query>> queries(N);
	// [node1] = (node2, query): query with index==query -> greater subtree rooted at node1
	// has any common vertex with less subtree rooted at node2?

	for(int query=0; query<(int)S.size(); ++query){
		int node1=greaterJump.get(S[query], L[query]);
		int node2=lessJump.get(N-1-E[query], N-1-R[query]);
		queries[node1].push_back({node2, query});
	}

	std::vector<int> result(S.size());

	// solve all queries

	/* // * not necessary
	auto const subtreeSize=[&]{ // of greater
		std::vector<int> result(N);
		auto const work=[&](auto work, int node)->int{
			auto cur=1;
			for(auto other: greaterAdd[node])
				cur+=work(work, other);
			return result[node]=cur;
		};
		for(auto it: greaterAdd[N]) work(work, it);
		for(auto it: result) assert(it>0);
		return result;
	}();
	*/

	auto const merge=[&](std::set<int> first, std::set<int> sec){
		if(first.size()<sec.size()) std::swap(first, sec);
		for(auto it: sec){
			auto const success=first.insert(it).second;
			assert(success);
		}
		return first;
	};

	std::vector<int> lessFirst(N), lessLast(N); // first and last index in preorder traversal of the less tree
	{ // construct ^
		int cur=0;
		auto const work=[&](auto work, int node)->void{
			assert(lessFirst[node]==0);
			lessFirst[node]=cur++;
			for(auto other: lessAdd[node])
				work(work, other);
			lessLast[node]=cur;
		};
		for(auto node: lessAdd[N]){
			work(work, node);
		}
		assert(cur==N);
	}

	// wait it's not necessary to compute subtreeSize if std::set is used anyway
	auto const work=[&](auto work, int node)->std::set<int>{
		std::set<int> curSet{lessFirst[N-1-node]};
		for(auto other: greaterAdd[node])
			curSet=merge(std::move(curSet), work(work, other));
		for(auto [node2, queryIndex]: queries[node]){
			auto const iterator=curSet.lower_bound(lessFirst[node2]);
			if(iterator!=curSet.end() and *iterator<lessLast[node2])
				result[queryIndex]=1;
		}
		return curSet;
	};
	for(auto it: greaterAdd[N]) work(work, it);

	return result;
}

Compilation message

werewolf.cpp: In lambda function:
werewolf.cpp:53:17: warning: unused variable 'success' [-Wunused-variable]
   53 |      auto const success=dsu.join(index, other);
      |                 ^~~~~~~
werewolf.cpp: In lambda function:
werewolf.cpp:137:15: warning: unused variable 'success' [-Wunused-variable]
  137 |    auto const success=first.insert(it).second;
      |               ^~~~~~~

Subtask #1

7.0 / 7.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	1 ms	384 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	1 ms	384 KB	Output is correct
4	Correct	1 ms	256 KB	Output is correct
5	Correct	1 ms	384 KB	Output is correct
6	Correct	1 ms	384 KB	Output is correct
7	Correct	1 ms	384 KB	Output is correct
8	Correct	1 ms	384 KB	Output is correct
9	Correct	1 ms	384 KB	Output is correct

Subtask #2

8.0 / 8.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	1 ms	384 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	1 ms	384 KB	Output is correct
4	Correct	1 ms	256 KB	Output is correct
5	Correct	1 ms	384 KB	Output is correct
6	Correct	1 ms	384 KB	Output is correct
7	Correct	1 ms	384 KB	Output is correct
8	Correct	1 ms	384 KB	Output is correct
9	Correct	1 ms	384 KB	Output is correct
10	Correct	8 ms	1536 KB	Output is correct
11	Correct	7 ms	1408 KB	Output is correct
12	Correct	7 ms	1152 KB	Output is correct
13	Correct	8 ms	1536 KB	Output is correct
14	Correct	10 ms	1536 KB	Output is correct
15	Correct	9 ms	1536 KB	Output is correct

Subtask #3

34.0 / 34.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	925 ms	58536 KB	Output is correct
2	Correct	1120 ms	86568 KB	Output is correct
3	Correct	984 ms	77096 KB	Output is correct
4	Correct	918 ms	71588 KB	Output is correct
5	Correct	929 ms	69864 KB	Output is correct
6	Correct	963 ms	71844 KB	Output is correct
7	Correct	842 ms	67748 KB	Output is correct
8	Correct	1084 ms	86568 KB	Output is correct
9	Correct	777 ms	76496 KB	Output is correct
10	Correct	714 ms	70700 KB	Output is correct
11	Correct	739 ms	69796 KB	Output is correct
12	Correct	793 ms	68844 KB	Output is correct
13	Correct	1252 ms	124456 KB	Output is correct
14	Correct	1214 ms	124268 KB	Output is correct
15	Correct	1216 ms	124528 KB	Output is correct
16	Correct	1232 ms	124520 KB	Output is correct
17	Correct	845 ms	67880 KB	Output is correct

Subtask #4

51.0 / 51.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	1 ms	384 KB	Output is correct
2	Correct	1 ms	384 KB	Output is correct
3	Correct	1 ms	384 KB	Output is correct
4	Correct	1 ms	256 KB	Output is correct
5	Correct	1 ms	384 KB	Output is correct
6	Correct	1 ms	384 KB	Output is correct
7	Correct	1 ms	384 KB	Output is correct
8	Correct	1 ms	384 KB	Output is correct
9	Correct	1 ms	384 KB	Output is correct
10	Correct	8 ms	1536 KB	Output is correct
11	Correct	7 ms	1408 KB	Output is correct
12	Correct	7 ms	1152 KB	Output is correct
13	Correct	8 ms	1536 KB	Output is correct
14	Correct	10 ms	1536 KB	Output is correct
15	Correct	9 ms	1536 KB	Output is correct
16	Correct	925 ms	58536 KB	Output is correct
17	Correct	1120 ms	86568 KB	Output is correct
18	Correct	984 ms	77096 KB	Output is correct
19	Correct	918 ms	71588 KB	Output is correct
20	Correct	929 ms	69864 KB	Output is correct
21	Correct	963 ms	71844 KB	Output is correct
22	Correct	842 ms	67748 KB	Output is correct
23	Correct	1084 ms	86568 KB	Output is correct
24	Correct	777 ms	76496 KB	Output is correct
25	Correct	714 ms	70700 KB	Output is correct
26	Correct	739 ms	69796 KB	Output is correct
27	Correct	793 ms	68844 KB	Output is correct
28	Correct	1252 ms	124456 KB	Output is correct
29	Correct	1214 ms	124268 KB	Output is correct
30	Correct	1216 ms	124528 KB	Output is correct
31	Correct	1232 ms	124520 KB	Output is correct
32	Correct	845 ms	67880 KB	Output is correct
33	Correct	1193 ms	83240 KB	Output is correct
34	Correct	395 ms	32888 KB	Output is correct
35	Correct	1339 ms	100432 KB	Output is correct
36	Correct	1154 ms	81580 KB	Output is correct
37	Correct	1308 ms	96828 KB	Output is correct
38	Correct	1212 ms	86440 KB	Output is correct
39	Correct	1234 ms	95600 KB	Output is correct
40	Correct	1170 ms	105772 KB	Output is correct
41	Correct	941 ms	92840 KB	Output is correct
42	Correct	792 ms	79912 KB	Output is correct
43	Correct	1367 ms	115892 KB	Output is correct
44	Correct	1079 ms	95784 KB	Output is correct
45	Correct	1052 ms	96552 KB	Output is correct
46	Correct	1112 ms	93348 KB	Output is correct
47	Correct	1244 ms	124584 KB	Output is correct
48	Correct	1242 ms	124196 KB	Output is correct
49	Correct	1218 ms	124456 KB	Output is correct
50	Correct	1216 ms	124324 KB	Output is correct
51	Correct	1020 ms	106152 KB	Output is correct
52	Correct	1004 ms	105896 KB	Output is correct