Submission #673384

#	Time	Username	Problem	Language	Result	Execution time	Memory
673384		Half	Logičari (COCI21_logicari)	C++17	110 / 110	163 ms	19484 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned long long int ull;
typedef long double ld;
#define REP(i,a,b) for(ll i=(ll) a; i<(ll) b; i++)
#define pb push_back
#define mp make_pair
#define pl pair<ll,ll>
#define ff first
#define ss second
#define whole(x) x.begin(),x.end()
#define DEBUG(i) cout<<"WAFFLES "<<i<<"<\n"
#define INF 10000000LL
#define EPS (0.00000000001L)
#define pi (3.141592653589793L)
#define VV(vvvv,NNNN,xxxx); REP(iiiii,0,NNNN) {vvvv.pb(xxxx);}
ll mod=1000000007LL;

template<class A=ll>
void Out(vector<A> a) {REP(i,0,a.size()) {cout<<a[i]<<" ";} cout<<endl;}

template<class A=ll>
void In(vector<A> &a, ll N) {A cur; REP(i,0,N) {cin>>cur; a.pb(cur);}} 

vector<vector<ll>> adj;
ll n;
vector<bool> vis;
pair<ll, ll> cyc;

pair<ll,ll> dfs(ll prv, ll nd){
	vis[nd] = true;
	pair<ll, ll> sol = {-1, -1};
	for(ll nb : adj[nd]){
		if(nb == prv)
			continue;
		if(vis[nb]){
			return {nd,nb};
		}
		sol = max(sol, dfs(nd, nb));
		if(sol.ff > -1)
			break;
	}
	return sol;
}

bool root_seeing, root_blue, cyc_blue;

vector<array<array<ll,2>,2>> mem;

ll tree_dfs(ll pr, ll nd, bool seeing, bool blue){
	if(mem[nd][seeing][blue] != -1)
		return mem[nd][seeing][blue];
	if(nd == cyc.ss){
		if(blue != root_seeing){
			mem[nd][seeing][blue] = INF;
			return INF;
		}
		if(seeing && root_blue){
			mem[nd][seeing][blue] = INF;
			return INF;
		}
		if(adj[nd].size() == 2){
			if(seeing || root_blue){
				mem[nd][seeing][blue] = blue;
				return blue;
			}else{
				mem[nd][seeing][blue] = INF;
				return INF;
			}
		}
		if(root_blue)
			seeing = true;
	}
	if(adj[nd].size() == 1){
		if(seeing){
			mem[nd][seeing][blue] = blue;
			return blue;
		}else{
			mem[nd][seeing][blue] = INF;
			return INF;
		}
	}
	if(seeing){
		if(blue){
			ll sum = 0;
			for(ll ch : adj[nd]){
				if(ch == pr)
					continue;
				if(ch == cyc.ff)
					continue;
				sum += tree_dfs(nd, ch, true, false);
			}
			mem[nd][seeing][blue] = sum+1;
			return sum + 1;
		}else{
			ll sum = 0;
			for(ll ch : adj[nd]){
				if(ch == pr)
					continue;
				if(ch == cyc.ff)
					continue;
				sum += tree_dfs(nd, ch, false, false);
			}
			mem[nd][seeing][blue] = sum;
			return sum;
		}
	}else{
		if(blue){
			ll sum = 0;
			ll mndf = INF;
			for(ll ch : adj[nd]){
				if(ch == pr)
					continue;
				if(ch == cyc.ff)
					continue;
				ll nb_ntb = tree_dfs(nd, ch, true, false);
				ll nb_b = tree_dfs(nd, ch, true, true);
				sum += nb_ntb;
				mndf = min(mndf, nb_b-nb_ntb);
			}
			mem[nd][seeing][blue] = sum + mndf + 1;
			return sum + mndf + 1;
		}else{
			ll sum = 0;
			ll mndf = INF;
			for(ll ch : adj[nd]){
				if(ch == pr)
					continue;
				if(ch == cyc.ff)
					continue;
				ll nb_ntb = tree_dfs(nd, ch, false, false);
				ll nb_b = tree_dfs(nd, ch, false, true);
				sum += nb_ntb;
				mndf = min(mndf, nb_b-nb_ntb);
			}
			mem[nd][seeing][blue] = sum + mndf;
			return sum + mndf;
		}
	}
}

int main(){
	ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cout.precision(20);

	cin >> n;
	adj.assign(n,{});
	ll a, b;
	for(ll i = 0; i < n; ++i){
		cin >> a >> b;
		a--;b--;
		adj[a].pb(b);
		adj[b].pb(a);
	}
	vis.assign(n, 0);
	cyc = dfs(-1, 0);
	mem.assign(n, {array<ll,2>{-1,-1},array<ll,2>{-1,-1}});
	ll mn = INF;
	root_seeing = false;
	root_blue = false;
	mn = min(mn, tree_dfs(cyc.ss, cyc.ff, false, false));
	mem.assign(n, {array<ll,2>{-1,-1},array<ll,2>{-1,-1}});
	root_seeing = false;
	root_blue = true;
	mn = min(mn, tree_dfs(cyc.ss, cyc.ff, false, true));

	mem.assign(n, {array<ll,2>{-1,-1},array<ll,2>{-1,-1}});
	root_seeing = true;
	root_blue = false;
	mn = min(mn, tree_dfs(cyc.ss, cyc.ff, true, false));
	mem.assign(n, {array<ll,2>{-1,-1},array<ll,2>{-1,-1}});
	root_seeing = true;
	root_blue = true;
	mn = min(mn, tree_dfs(cyc.ss, cyc.ff, true, true));
	if(mn >= INF){
		cout << "-1\n";
	}else{
		cout << mn << "\n";
	}
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 40 / 40
• Subtask 4: 50 / 50