Submission #1040062

#	Time	Username	Problem	Language	Result	Execution time	Memory
1040062		Alihan_8	Keys (IOI21_keys)	C++17	100 / 100	512 ms	80828 KiB

keys

#include <vector>

#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
//#define int long long

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

std::vector<int> find_reachable(std::vector<int> r, std::vector<int> u, std::vector<int> v, std::vector<int> c) {
	int n = r.size(), m = u.size();
	
	vector <vector<ar<int,2>>> adj(n);
	
	for ( int i = 0; i < m; i++ ){
		adj[u[i]].pb({v[i], c[i]});
		adj[v[i]].pb({u[i], c[i]});
	}
	
	vector <vector<int>> C(n);
	
	vector <int> fa(n), rt(n);
	
	for ( int i = 0; i < n; i++ ){
		C[i].pb(i);
		fa[i] = rt[i] = i;
	}
	
	vector <int> us(n), vis(n), er, erK; // us - keys, vis - vertex
		
	vector <vector<int>> need(n);
	
	auto get = [&](int x){
		queue <int> q;
			
		q.push(x);
		
		while ( !q.empty() ){
			int u = q.front();
			q.pop();
			
			if ( vis[u] ) continue;
			
			if ( us[r[u]] == 0 ){
				for ( auto &v: need[r[u]] ){
					q.push(v);
					
					if ( fa[v] != fa[x] ){
						return fa[v];
					}
				}
			}
			
			vis[u] = us[r[u]] = true;
			
			er.pb(u);
			
			for ( auto &[v, c]: adj[u] ){
				if ( us[c] ){
					q.push(v);
					
					if ( fa[v] != fa[x] ){
						return fa[v];
					}
				} else{
					need[c].pb(v);
					
					erK.pb(c);
				}
			}
		}
		
		return -1;
	};
	
	auto clear = [&](){
		for ( auto &u: er ){
			vis[u] = us[r[u]] = 0;
		} er.clear();
		
		for ( auto &u: erK ){
			need[u].clear();
		} erK.clear();
	};
	
	vector <int> K(n, 1); // random stuff
	
	while ( true ){
		vector <int> to(n, -1);
		
		for ( int x = 0; x < n; x++ ){
			if ( fa[x] != x ) continue;
			
			to[x] = get(rt[x]);
			
			clear();
		}
		
		//~ cout << "Components\n";
		
		//~ for ( int i = 0; i < n; i++ ){
			//~ auto &x = C[i];
			
			//~ if ( x.empty() ) continue;
			
			//~ for ( auto &u: x ) cout << u << ' '; 
			
			//~ cout << "  ->  " << rt[i] << ln;
			//~ cout << ln;
		//~ } cout << ln;
		
		//~ for ( auto &x: to ) cout << x << " "; 
		//~ cout << "\n\n";
		
		bool hasMerged = false;
		
		for ( int i = 0; i < n; i++ ){
			if ( i != fa[i] || to[i] == -1 ) continue;
			
			int v = fa[to[i]];
			
			if ( i == v ) continue;
			
			if( C[v].empty() ) return K;
			
			hasMerged = true;
			
			if ( C[i].size() > C[v].size() ){
				rt[i] = rt[v];
				
				for ( auto &x: C[v] ){
					C[i].pb(x);
					
					fa[x] = i;
				} C[v].clear();
			} else{
				for ( auto &x: C[i] ){
					C[v].pb(x);
					
					fa[x] = v;
				} C[i].clear();
			}
		}
		
		if ( !hasMerged ) break;
	}
	
	vector <int> ans;
	
	int mn = n + 1;
	
	for ( int x = 0; x < n; x++ ){
		if ( x != fa[x] ) continue;
		
		get(rt[x]);
		
		int s = er.size();
		
		if ( chmin(mn, s) ){
			ans = er;
		} else if ( s == mn ){
			for ( auto &u: er ){
				ans.pb(u);
			}
		}
		
		clear();
	}
	
	vector <int> ret(n);
	
	for ( auto &x: ans ) ret[x] = 1;
	
	return ret;
}

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 30 / 30
• Subtask 5: 33 / 33