oj.uz

Submission #288227

# Submission time Handle Problem Language Result Execution time Memory
288227 2020-09-01T10:35:44 Z user202729 Simurgh (IOI17_simurgh) C++17
70 / 100
 543 ms 7128 KB 
// moreflags=grader.cpp
// 11
// :(
#include "simurgh.h"
#if not LOCAL
#define NDEBUG
#endif
#include<cassert>
#include<algorithm>

struct Dsu{
	std::vector<int> data;
	Dsu(int number){reset(number);}
	void reset(int number){data.assign(number, -1);}
	int root(int node){return data[node]>=0 ? data[node]=root(data[node]): node;}
	bool join(int first, int sec){
		first=root(first); sec=root(sec);
		if(first==sec) return false;
		data[first]=sec;
		return true;
	}
};

struct Edge{int node, index;};
std::vector<std::vector<Edge>> add;
std::vector<int> par, depth, parIndex;
std::vector<char> visited;

void work(int node, int curPar, int curDepth){
	par[node]=curPar; depth[node]=curDepth;
	assert(not visited[node]); visited[node]=true;
	for(auto [child, index]: add[node]) if(not visited[child]){
		parIndex[child]=index;
		work(child, node, curDepth+1);
	}
}

std::vector<int> find_roads(int n, std::vector<int> u, std::vector<int> v) {
	// construct a DFS tree
	add.resize(n);
	for(int index=0; index<(int)u.size(); ++index){
		auto const first=u[index], sec=v[index];
		add[first].push_back({sec, index});
		add[sec].push_back({first, index});
	}
	par.resize(n); depth.resize(n);
	visited.assign(n, false);
	parIndex.resize(n); parIndex[0]=-1;
	work(0, -1, 0);

	// compute value of that tree
	std::vector<int> tmp; tmp.reserve(n-1);
	for(int node=0; node<n; ++node)
		for(auto [other, index]: add[node]) if(depth[other]==depth[node]-1)
			tmp.push_back(index);
	int const treeValue=count_common_roads(tmp);

	// compute individual edges' values
	std::vector<int> value(u.size(), -1);
	for(int node=0; node<n; ++node){
		for(auto [other, backIndex]: add[node]) if(depth[other]<depth[node]-1){
			// back edge
			int& backValue=value[backIndex];
			assert(backValue==-1);

			for(int x=node; x!=other; x=par[x]){
				if(value[parIndex[x]]<0) goto anyUndefined;
			}
			continue;

anyUndefined:
			bool guessBackValue=true;
			backValue=0; // this is the guess.


			for(int x=node; x!=other; x=par[x]){
				auto const fixWrongBackValueGuess=[&]{
					for(int y=node; y!=x; y=par[y]){
						assert(value[parIndex[y]]==0); value[parIndex[y]]=1;
					}
				};
			
				int& curValue=value[parIndex[x]];
				if(guessBackValue or curValue<0){
					auto const iterator=std::find(begin(tmp), end(tmp), parIndex[x]);
					*iterator=backIndex;
					auto const v=count_common_roads(tmp)-treeValue; // == backValue-curValue
					*iterator=parIndex[x];

					switch(v){
						case 0:
							{
								if(curValue>=0){
									if(guessBackValue){
										assert(backValue==0); backValue=curValue;
										if(curValue==1) fixWrongBackValueGuess();

										guessBackValue=false;
									}else{
										assert(curValue==backValue);
									}
								}else{
									curValue=backValue;
								}
								break;
							}
						case -1:
							{
								assert(curValue!=0); curValue=1;
								assert(backValue==0);
								if(guessBackValue){
									guessBackValue=false; // already guessed correctly
								}
								break;
							}
						case 1:
							{
								assert(v==1);
								assert(curValue!=1);
								if(guessBackValue){
									assert(backValue==0); backValue=1;
									fixWrongBackValueGuess();
								}else assert(backValue==1);
								curValue=0; backValue=1; guessBackValue=false;
								break;

							}
						default:
							assert(false); __builtin_unreachable();
					}
				}
			}

			if(guessBackValue){
				assert(backValue==0);
				for(int x=node; x!=other; x=par[x])
					assert(value[parIndex[x]]==0);
				// also guessed correctly (there's no way the values of all those edges can be 1 at the same time)
			}
		}
	}

	// double check that tmp is the DFS tree
	for(int node=0; node<n; ++node)
		for(auto [other, index]: add[node]) if(depth[other]==depth[node]-1){
			assert(std::find(begin(tmp), end(tmp), index)!=tmp.end());
		}

	for(auto index: tmp)
		if(value[index]==-1) value[index]=1; // a bridge

	auto const treeEdges=std::move(tmp); tmp.clear();
	tmp.reserve(n-1);
	std::vector<std::pair<Dsu, std::vector<int>>> trees;
	trees.push_back({Dsu(n), {}});
	for(int index=0; index<(int)value.size(); ++index)
		if(value[index]<0){
			[&]{
				if(not trees.back().second.empty())
					trees.push_back({Dsu(n), {}});
				for(auto& [dsu, edges]: trees){
					if(dsu.join(u[index], v[index])){
						edges.push_back(index); return;
					}
				}
				assert(false); __builtin_unreachable();
			}();
		}
	while(not trees.empty() and trees.back().second.empty()) trees.pop_back();
	assert((int)trees.size()<=n-1);

	assert(tmp.empty());

	auto const process=[&](auto process, auto first, auto last)->void{
		Dsu dsu(n);
		std::for_each(first, last,[&](int index){
			assert(value[index]<0);
			dsu.join(u[index], v[index]);
		});
		if(first==last) return;

		assert(tmp.empty()); tmp.assign(first, last);

		int extra=0;
		for(auto index: treeEdges) if(dsu.join(u[index], v[index])){
			assert(value[index]>=0); extra+=value[index];
			tmp.push_back(index);
		}
		assert((int)tmp.size()==n-1);

		int const count=count_common_roads(tmp)-extra;
#if LOCAL
		auto const store=tmp;
#endif
		tmp.clear();
		if(count==last-first)
			std::for_each(first, last,[&](int index){ value[index]=1; });
		else if(count==0)
			std::for_each(first, last,[&](int index){ value[index]=0; });
		else{
			assert(0<count); assert(count<last-first);
			auto const middle=first+((last-first)>>1);
			process(process, first, middle);
			process(process, middle, last);
		}
	};

	for(auto& [dsu, edges]: trees){
		process(process, begin(edges), end(edges));
		edges.clear();
	}
	trees.clear();

	assert(tmp.empty());
	for(int index=0; index<(int)value.size(); ++index){
		assert(value[index]>=0);
		if(value[index]) tmp.push_back(index);
	}
	return tmp;
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 256 KB correct
2 Correct 0 ms 256 KB correct
3 Correct 0 ms 256 KB correct
4 Correct 0 ms 256 KB correct
5 Correct 0 ms 256 KB correct
6 Correct 1 ms 256 KB correct
7 Correct 0 ms 256 KB correct
8 Correct 0 ms 256 KB correct
9 Correct 0 ms 256 KB correct
10 Correct 0 ms 256 KB correct
11 Correct 0 ms 256 KB correct
12 Correct 1 ms 256 KB correct
13 Correct 0 ms 256 KB correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 256 KB correct
2 Correct 0 ms 256 KB correct
3 Correct 0 ms 256 KB correct
4 Correct 0 ms 256 KB correct
5 Correct 0 ms 256 KB correct
6 Correct 1 ms 256 KB correct
7 Correct 0 ms 256 KB correct
8 Correct 0 ms 256 KB correct
9 Correct 0 ms 256 KB correct
10 Correct 0 ms 256 KB correct
11 Correct 0 ms 256 KB correct
12 Correct 1 ms 256 KB correct
13 Correct 0 ms 256 KB correct
14 Correct 3 ms 384 KB correct
15 Correct 3 ms 384 KB correct
16 Correct 3 ms 384 KB correct
17 Correct 3 ms 384 KB correct
18 Correct 2 ms 384 KB correct
19 Correct 2 ms 384 KB correct
20 Correct 3 ms 384 KB correct
21 Correct 2 ms 384 KB correct
22 Correct 1 ms 384 KB correct
23 Correct 1 ms 384 KB correct
24 Correct 1 ms 384 KB correct
25 Correct 0 ms 256 KB correct
26 Correct 1 ms 384 KB correct
27 Correct 1 ms 384 KB correct
28 Correct 1 ms 256 KB correct
29 Correct 1 ms 256 KB correct
30 Correct 1 ms 384 KB correct
31 Correct 1 ms 384 KB correct
32 Correct 1 ms 384 KB correct
33 Correct 1 ms 304 KB correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 256 KB correct
2 Correct 0 ms 256 KB correct
3 Correct 0 ms 256 KB correct
4 Correct 0 ms 256 KB correct
5 Correct 0 ms 256 KB correct
6 Correct 1 ms 256 KB correct
7 Correct 0 ms 256 KB correct
8 Correct 0 ms 256 KB correct
9 Correct 0 ms 256 KB correct
10 Correct 0 ms 256 KB correct
11 Correct 0 ms 256 KB correct
12 Correct 1 ms 256 KB correct
13 Correct 0 ms 256 KB correct
14 Correct 3 ms 384 KB correct
15 Correct 3 ms 384 KB correct
16 Correct 3 ms 384 KB correct
17 Correct 3 ms 384 KB correct
18 Correct 2 ms 384 KB correct
19 Correct 2 ms 384 KB correct
20 Correct 3 ms 384 KB correct
21 Correct 2 ms 384 KB correct
22 Correct 1 ms 384 KB correct
23 Correct 1 ms 384 KB correct
24 Correct 1 ms 384 KB correct
25 Correct 0 ms 256 KB correct
26 Correct 1 ms 384 KB correct
27 Correct 1 ms 384 KB correct
28 Correct 1 ms 256 KB correct
29 Correct 1 ms 256 KB correct
30 Correct 1 ms 384 KB correct
31 Correct 1 ms 384 KB correct
32 Correct 1 ms 384 KB correct
33 Correct 1 ms 304 KB correct
34 Correct 86 ms 1784 KB correct
35 Correct 85 ms 1784 KB correct
36 Correct 64 ms 1640 KB correct
37 Correct 14 ms 384 KB correct
38 Correct 84 ms 1784 KB correct
39 Correct 73 ms 1792 KB correct
40 Correct 63 ms 1552 KB correct
41 Correct 87 ms 1784 KB correct
42 Correct 84 ms 1804 KB correct
43 Correct 20 ms 1352 KB correct
44 Correct 15 ms 1024 KB correct
45 Correct 19 ms 1076 KB correct
46 Correct 14 ms 896 KB correct
47 Correct 8 ms 640 KB correct
48 Correct 2 ms 384 KB correct
49 Correct 5 ms 384 KB correct
50 Correct 8 ms 640 KB correct
51 Correct 18 ms 1144 KB correct
52 Correct 16 ms 1024 KB correct
53 Correct 14 ms 896 KB correct
54 Correct 20 ms 1280 KB correct
55 Correct 18 ms 1152 KB correct
56 Correct 19 ms 1152 KB correct
57 Correct 23 ms 1152 KB correct

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 256 KB correct
2 Correct 1 ms 256 KB correct
3 Correct 296 ms 4856 KB correct
4 Correct 536 ms 6904 KB correct
5 Correct 527 ms 6904 KB correct
6 Correct 526 ms 6776 KB correct
7 Correct 524 ms 6776 KB correct
8 Correct 529 ms 6780 KB correct
9 Correct 528 ms 6776 KB correct
10 Correct 531 ms 7128 KB correct
11 Correct 530 ms 6776 KB correct
12 Correct 536 ms 6904 KB correct
13 Correct 1 ms 256 KB correct
14 Correct 543 ms 6776 KB correct
15 Correct 524 ms 6904 KB correct

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 256 KB correct
2 Correct 0 ms 256 KB correct
3 Correct 0 ms 256 KB correct
4 Correct 0 ms 256 KB correct
5 Correct 0 ms 256 KB correct
6 Correct 1 ms 256 KB correct
7 Correct 0 ms 256 KB correct
8 Correct 0 ms 256 KB correct
9 Correct 0 ms 256 KB correct
10 Correct 0 ms 256 KB correct
11 Correct 0 ms 256 KB correct
12 Correct 1 ms 256 KB correct
13 Correct 0 ms 256 KB correct
14 Correct 3 ms 384 KB correct
15 Correct 3 ms 384 KB correct
16 Correct 3 ms 384 KB correct
17 Correct 3 ms 384 KB correct
18 Correct 2 ms 384 KB correct
19 Correct 2 ms 384 KB correct
20 Correct 3 ms 384 KB correct
21 Correct 2 ms 384 KB correct
22 Correct 1 ms 384 KB correct
23 Correct 1 ms 384 KB correct
24 Correct 1 ms 384 KB correct
25 Correct 0 ms 256 KB correct
26 Correct 1 ms 384 KB correct
27 Correct 1 ms 384 KB correct
28 Correct 1 ms 256 KB correct
29 Correct 1 ms 256 KB correct
30 Correct 1 ms 384 KB correct
31 Correct 1 ms 384 KB correct
32 Correct 1 ms 384 KB correct
33 Correct 1 ms 304 KB correct
34 Correct 86 ms 1784 KB correct
35 Correct 85 ms 1784 KB correct
36 Correct 64 ms 1640 KB correct
37 Correct 14 ms 384 KB correct
38 Correct 84 ms 1784 KB correct
39 Correct 73 ms 1792 KB correct
40 Correct 63 ms 1552 KB correct
41 Correct 87 ms 1784 KB correct
42 Correct 84 ms 1804 KB correct
43 Correct 20 ms 1352 KB correct
44 Correct 15 ms 1024 KB correct
45 Correct 19 ms 1076 KB correct
46 Correct 14 ms 896 KB correct
47 Correct 8 ms 640 KB correct
48 Correct 2 ms 384 KB correct
49 Correct 5 ms 384 KB correct
50 Correct 8 ms 640 KB correct
51 Correct 18 ms 1144 KB correct
52 Correct 16 ms 1024 KB correct
53 Correct 14 ms 896 KB correct
54 Correct 20 ms 1280 KB correct
55 Correct 18 ms 1152 KB correct
56 Correct 19 ms 1152 KB correct
57 Correct 23 ms 1152 KB correct
58 Correct 0 ms 256 KB correct
59 Correct 1 ms 256 KB correct
60 Correct 296 ms 4856 KB correct
61 Correct 536 ms 6904 KB correct
62 Correct 527 ms 6904 KB correct
63 Correct 526 ms 6776 KB correct
64 Correct 524 ms 6776 KB correct
65 Correct 529 ms 6780 KB correct
66 Correct 528 ms 6776 KB correct
67 Correct 531 ms 7128 KB correct
68 Correct 530 ms 6776 KB correct
69 Correct 536 ms 6904 KB correct
70 Correct 1 ms 256 KB correct
71 Correct 543 ms 6776 KB correct
72 Correct 524 ms 6904 KB correct
73 Correct 0 ms 256 KB correct
74 Incorrect 521 ms 6776 KB WA in grader: NO
75 Halted 0 ms 0 KB -