Submission #1201827

#	Time	Username	Problem	Language	Result	Execution time	Memory
1201827		Zbyszek99	Simurgh (IOI17_simurgh)	C++20	0 / 100	3 ms	6212 KiB

simurgh

#include "simurgh.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;

vector<pii> graph[501];
int val[501*501];
int edge_num[501][501];
vi end_points[501*501];
bool odw[501];
int pre[501];
int low[501];
int odw_path[501];
int cur_pre = 0;
bool bridges[501*501];
vi known_tree;
vi comp = {};
int n;

void dfs_low(int v, int pop)
{
	pre[v] = cur_pre++;
	low[v] = pre[v];
	odw[v] = 1;
	forall(it,graph[v])
	{
		if(it.ff != pop)
		{
			if(odw[it.ff])
			{
				low[v] = min(pre[it.ff],low[v]);
			}
			else
			{
				dfs_low(it.ff,v);
				low[v] = min(low[v],low[it.ff]);
				if(low[it.ff] == pre[it.ff])
				{
					bridges[it.ss] = 1;
					val[it.ss] = 1;
					known_tree.pb(it.ss);
				}
			}
		}
	}
}

void dfs_comp(int v)
{
	comp.pb(v);
	odw[v] = 1;
	forall(it,graph[v])
	{
		if(odw[it.ff] == 0 && !bridges[it.ss])
		{
			dfs_comp(it.ff);
		}
	}
}

vi path;

void gen_path(int v, int pop)
{
	path.pb(v);
	if(odw[v] == 1 && v != pop)
	{
		return;
	}
	forall(it,graph[v])
	{
		if(!bridges[it.ss] && it.ff != pop && (odw[it.ff] == 0 || v != pop))
		{
			gen_path(it.ff,v);
			return;
		}
	}
}

vi cur_p;
vi doc_path;
int ci = 0;

void dfs_path(int v, int doc)
{
	cur_p.pb(v);
	if(v == doc)
	{
		doc_path = cur_p;
		return;
	}
	odw_path[v] = ci;
	forall(it,graph[v])
	{
		if(odw[it.ff] == 1 && odw_path[it.ff] != ci)
		{
			dfs_path(it.ff,doc);
			if(siz(doc_path) != 0) return;
		}
	}
	cur_p.pop_back();
}

vi rng_tree;

void find_random_tree(int v)
{
	odw_path[v] = ci;
	forall(it,graph[v])
	{
		if(odw_path[it.ff] != ci)
		{
			rng_tree.pb(it.ss);
			find_random_tree(it.ff);
		}
	}
}

void find_cycle_vals(vi edge, vi verts)
{
	rng_tree = {};
	ci++;
	forall(it,verts) odw_path[it] = ci;
	forall(it,verts) find_random_tree(it);
	forall(it,edge) known_tree.pb(it);
	int ke = -1;
	forall(it,edge) if(val[it] != -1) ke = it;
	if(ke != -1)
	{
		vi query_tree = rng_tree;
		forall(it,edge) if(it != ke) query_tree.pb(it);
		int ke_val = count_common_roads(query_tree);
		rep(i,siz(edge)-1) query_tree.pop_back();
		forall(it,edge)
		{
			if(val[it] != -1) continue;
			forall(it2,edge)
			{
				if(it != it2) query_tree.pb(it2);
			}
			if(ke_val == count_common_roads(query_tree)) val[it] = val[ke];
			else val[it] = val[ke] ^ 1;
			rep(i,siz(edge)-1) query_tree.pop_back();
		}
	}
	else
	{
		vi query_tree = rng_tree;
		int max_ = -1e9;
		int min_ = 1e9;
		forall(it,edge)
		{
			if(val[it] != -1) continue;
			forall(it2,edge)
			{
				if(it != it2) query_tree.pb(it2);
			}
			val[it] = count_common_roads(query_tree);
			min_ = min(min_,val[it]);
			max_ = max(max_,val[it]);
			rep(i,siz(edge)-1) query_tree.pop_back();
		}
		if(min_ == max_) forall(it,edge) val[it] = 0;
		else
		{
			forall(it,edge)
			{
				if(val[it] == min_) val[it] = 1;
				else val[it] = 0;
			}
		}
	}
}

int rep_[501];

int fint(int v)
{
	if(rep_[v] == v) return v;
	rep_[v] = fint(rep_[v]);
	return rep_[v];
}

void onion(int a, int b)
{
	rep_[fint(a)] = fint(b);
}

int count_forest_val(vi f)
{
	rep(i,n) rep_[i] = i;
	int known_sum = 0;
	vi query_tree = f;
	forall(it,f) onion(end_points[it][0],end_points[it][1]);
	forall(it,known_tree)
	{
		if(fint(end_points[it][0]) != fint(end_points[it][1]))
		{
			known_sum += val[it];
			query_tree.pb(it);
			onion(end_points[it][0],end_points[it][1]);
		}
	}
	return count_common_roads(query_tree) - known_sum;
}

vi find_roads(int N, vi u, vi v) 
{
	n = N;
	rep(i,siz(u))
	{
		val[i] = -1;
		end_points[i] = {v[i],u[i]};
		graph[u[i]].pb({v[i],i});
		graph[v[i]].pb({u[i],i});
		edge_num[u[i]][v[i]] = i;
		edge_num[v[i]][u[i]] = i;
	}	
	dfs_low(0,0);
	rep(i,n) odw[i] = 0;
	rep(i,n)
	{
		if(odw[i] == 0)
		{
			comp = {};
			dfs_comp(i);
			if(siz(comp) == 1) continue;
			forall(it,comp) 
			{
				odw[it] = 0;
			}
			queue<int> q;
			q.push(i);
			odw[i] = 1;
			while(!q.empty())
			{
				int t = q.front();
				q.pop();
				while(true)
				{
					path = {};
					gen_path(t,t);
					if(siz(path) == 1) break;
					ci++;
					cur_p = {};
					doc_path = {};
					dfs_path(path.back(),path[0]);
					forall(it,path) 
					{
						if(odw[it] == 0)
						{
							q.push(it);
						}
						odw[it] = 1;
					}
					vi total_path = path;
					total_path.pop_back();
					forall(it,doc_path) total_path.pb(it);
					vi cycle_edges;
					rep(i,siz(total_path)-1)
					{
						cycle_edges.pb(edge_num[total_path[i]][total_path[i+1]]);
					}
					find_cycle_vals(cycle_edges,total_path);
				}
			}
		}
	}
	rep(i,n)
	{
		vi unknown;
		forall(it,graph[i])
		{
			if(val[it.ss] == -1) unknown.pb(it.ss);
		} 
		int deg = count_forest_val(unknown);
		if(deg == 0)
		{
			forall(it,graph[i])
			{
				if(val[it.ss] == -1) val[it.ss] = 0;
			}
			continue;
		}
		rep(j,deg)
		{
			vi s;
			forall(it,unknown) if(val[it] == -1) s.pb(it);
			while(siz(s) != 1)
			{
				vi left;
				vi right;
				rep(i,siz(s)/2) left.pb(s[i]);
				rep(i,(siz(s)+1)/2) right.pb(s[i]);
				if(count_forest_val(left) > 0) s = left;
				else s = right;
			}
			val[s[0]] = 1;
		}
	}
	vi ans;
	rep(i,siz(u))
	{
		if(val[i] == 1) ans.pb(i);
	}
	return ans;
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 17
• Subtask 3: 0 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30