Submission #1264835

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264835		thelegendary08	Logičari (COCI21_logicari)	C++17	110 / 110	60 ms	23236 KiB

Main

#include<bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define int long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define vc vector<char>
#define vb vector<bool>
#define mii map<int,int>
#define f0r(i,n) for(int i=0;i<n;i++)
#define FOR(i,k,n) for(int i=k;i<n;i++)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define in(a) int a; cin>>a
#define in2(a,b) int a,b; cin>>a>>b
#define in3(a,b,c) int a,b,c; cin>>a>>b>>c
#define in4(a,b,c,d) int a,b,c,d; cin>>a>>b>>c>>d
#define vin(v,n); vi v(n); f0r(i,n){cin>>v[i];}
#define out(a) cout<<a<<'\n'
#define out2(a,b) cout<<a<<' '<<b<<'\n'
#define out3(a,b,c) cout<<a<<' '<<b<<' '<<c<<'\n'
#define out4(a,b,c,d) cout<<a<<' '<<b<<' '<<c<<' '<<d<<'\n'
#define pout(a) cout<<a.first<<' '<<a.second<<'\n'
#define vout(v) for(auto u : v){cout<<u<<' ';} cout<<endl
#define dout(a) cout<<a<<' '<<#a<<endl
#define dout2(a,b) cout<<a<<' '<<#a<<' '<<b<<' '<<#b<<endl
#define yn(x); if(x){cout<<"YES"<<'\n';}else{cout<<"NO"<<'\n';}
const int leg = 1e9 + 7;
const int mod = 998244353;
using namespace std;
const int mxn = 1e5 + 5; 
const int ch = 0; 
const int pa = 1; 
const int L = 0, R = 1; 
vvi adj(mxn);
vb vis(mxn); 
vi cycle;
vi par(mxn, -1);
vb incyc(mxn); 
int dp[mxn][2][2], f[mxn][2][2]; 
  
void dfs(int node, int from){
	vis[node] = 1; 
	if(!cycle.empty())return; 
	for(auto u : adj[node]){
		if(u == from)continue; 
		if(vis[u]){
			int cur = node; 
			while(1){
				cycle.pb(cur); 
				if(cur == u)break; 
				cur = par[cur]; 
			}
		}
		else{
			par[u] = node; 
			dfs(u, node); 
		}
		
		if(!cycle.empty())return; 
	}
}

void add(int &a, int &b){
	if(a == -1)return; 
	if(b == -1)a = -1; 
	else a += b; 
}

void solve(int node, int from){
	int deg = 0; 
	for(auto u : adj[node]){
		if(incyc[u] || u == from)continue; 
		solve(u, node); deg++; 
	}
	
	if(deg == 1){
		dp[node][0][pa] = 0; 
		dp[node][1][pa] = 1; 
	}
	
	f0r(i, 2)f0r(j, 2)dp[node][i][j] = i; 
	int cant = 0, sum = 0; 
	int autis = -1; 
	for(auto u : adj[node]){
		if(incyc[u] || u == from)continue; 
		add(dp[node][0][pa], dp[u][0][ch]); 
		add(dp[node][1][pa], dp[u][0][pa]); 
		if(dp[u][0][ch] == -1)cant++, autis = u; 
		else sum += dp[u][0][ch]; 
	}
	if(cant == 0){
		int mx = 1e9; 
		for(auto u : adj[node]){
			if(incyc[u] || u == from)continue; 
			if(dp[u][1][ch] != -1){
				mx = min(mx, sum - dp[u][0][ch] + dp[u][1][ch]); 
			}
		}
		if(mx == 1e9)dp[node][0][ch] = -1; 
		else dp[node][0][ch] += mx; 
	}
	else if(cant == 1){
		if(dp[autis][1][ch] != -1){
			dp[node][0][ch] += sum + dp[autis][1][ch]; 
		}
		else dp[node][0][ch] = -1; 
	}
	else{
		dp[node][0][ch] = -1; 
	}
	
	cant = 0, sum = 0; 
	autis = -1; 
	for(auto u : adj[node]){
		if(incyc[u] || u == from)continue; 
		if(dp[u][0][pa] == -1)cant++, autis = u; 
		else sum += dp[u][0][pa]; 
	}
	if(cant == 0){
		int mx = 1e9; 
		for(auto u : adj[node]){
			if(incyc[u] || u == from)continue; 
			if(dp[u][1][pa] != -1){
				mx = min(mx, sum - dp[u][0][pa] + dp[u][1][pa]); 
			}
		}
		if(mx == 1e9)dp[node][1][ch] = -1; 
		else dp[node][1][ch] += mx; 
	}
	else if(cant == 1){
		if(dp[autis][1][pa] != -1){
			dp[node][1][ch] += sum + dp[autis][1][pa]; 
		}
		else dp[node][1][ch] = -1; 
	}
	else{
		dp[node][1][ch] = -1; 
	}
}


signed main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	//ifstream cin(".in");
	//ofstream cout(".out");
	in(n);
	f0r(i, n){
		f0r(j, 2)f0r(k, 2)dp[i][j][k] = -1; 
	}
	f0r(i,n){
		in2(a,b); a--; b--; 
		adj[a].pb(b); adj[b].pb(a); 
	}
	
	dfs(0, -1); 
	reverse(all(cycle));
	for(auto u : cycle)incyc[u] = 1; 
	for(auto u : cycle){
		solve(u, -1);
	}
	// f0r(i, cycle.size()){
		// cout<<cycle[i]<<' ';
	// }
	// cout<<'\n';
	f0r(i, cycle.size())f0r(j,2)f0r(k,2){
		f[i][j][k] = dp[cycle[i]][j][k];
	}
	
	//f[root][colour of self][number of coloured neighbours]
	int ans = 1e9; 
	
	f0r(si, 2)f0r(sj, 2)f0r(sk, 2)if(!(sj == 0 && sk == R) && f[0][si][sj] != -1){
		int g[cycle.size()][2][2][2]; 
		f0r(i, 2)f0r(j, 2)f0r(k, 2){
			g[0][i][j][k] = -1; 
		}
		g[0][si][sj][sk] = f[0][si][sj]; 
		// out3(si,sj,sk);
		// out(f[0][si][sj]); 
		FOR(v, 1, cycle.size()){
			f0r(i, 2)f0r(j,2)f0r(k,2)if(!(j == 0 && k == R)){
				g[v][i][j][k] = f[v][i][j]; 
				int mn = 1e9; 
				if(g[v][i][j][k] != -1){
					if(i == 0 && j == 1 && k == L){
						if(g[v-1][1][1][L] != -1){
							mn = min(mn, g[v-1][1][1][L]);
						}
						if(g[v-1][1][0][L] != -1){
							mn = min(mn, g[v-1][1][0][L]); 
						}
						if(mn != 1e9)g[v][i][j][k] += mn; 
						else g[v][i][j][k] = -1; 
					}
					else if(i == 0 && j == 1 && k == R){
						if(g[v-1][0][1][L] != -1){
							mn = min(mn, g[v-1][0][1][L]);
						}
						if(g[v-1][0][0][L] != -1){
							mn = min(mn, g[v-1][0][0][L]); 
						}
						if(mn != 1e9)g[v][i][j][k] += mn; 
						else g[v][i][j][k] = -1; 
					}
					else if(i == 1 && j == 1 && k == L){
						if(g[v-1][1][1][R] != -1){
							mn = min(mn, g[v-1][1][1][R]);
						}
						if(mn != 1e9)g[v][i][j][k] += mn; 
						else g[v][i][j][k] = -1; 
					}
					else if(i == 1 && j == 1 && k == R){
						if(g[v-1][0][1][R] != -1){
							mn = min(mn, g[v-1][0][1][R]);
						}
						if(mn != 1e9)g[v][i][j][k] += mn; 
						else g[v][i][j][k] = -1; 
					}
					else if(i == 0 && j == 0){
						if(g[v-1][0][1][L] != -1){
							mn = min(mn, g[v-1][0][1][L]);
						}
						if(g[v-1][0][0][L] != -1){
							mn = min(mn, g[v-1][0][0][L]); 
						}
						if(mn != 1e9)g[v][i][j][k] += mn; 
						else g[v][i][j][k] = -1; 
					}
					else{
						if(g[v-1][0][1][R] != -1){
							mn = min(mn, g[v-1][0][1][R]);
						}
						if(mn != 1e9)g[v][i][j][k] += mn; 
						else g[v][i][j][k] = -1; 
					}
				}
				
			}
			
		}
		tuple<int,int,int>t = {si,sj,sk}; 
		/*
		if(t == mt(1,1,R)){
			// dout(g[1][1][1][L]);
			f0r(i,cycle.size())f0r(j, 2)f0r(k,2)f0r(l,2){
				if(g[i][j][k][l] == 0)out4(i,j,k,l);
			}
		}
		*/
		f0r(i, 2)f0r(j,2)f0r(k,2)if(!(j == 0 && k == R)){
			tuple<int,int,int>s = {i,j,k}; 
			if(s == mt(0,1,L)){
				if(t == mt(0,1,R) || t == mt(0,0,L))if(g[cycle.size() - 1][i][j][k] != -1){
					ans = min(ans, g[cycle.size() - 1][i][j][k]);
				}
			}
			else if(s == mt(0,1,R)){
				if(t == mt(1,1,R) || t == mt(1,0,L))if(g[cycle.size() - 1][i][j][k] != -1){
					// out("HERE");
					// dout(g[cycle.size() - 1][i][j][k]);
					// dout2(si,sj);
					ans = min(ans, g[cycle.size() - 1][i][j][k]);
				}
			}
			else if(s == mt(1,1,L)){
				if(t == mt(0,1,L))if(g[cycle.size() - 1][i][j][k] != -1){
					ans = min(ans, g[cycle.size() - 1][i][j][k]);
				}
			}
			else if(s == mt(1,1,R)){
				if(t == mt(1,1,L))if(g[cycle.size() - 1][i][j][k] != -1){
					ans = min(ans, g[cycle.size() - 1][i][j][k]);
				}
			}
			else if(s == mt(0,0,L)){
				if(t == mt(0,0,L) || t == mt(0,1,R))if(g[cycle.size() - 1][i][j][k] != -1){
					ans = min(ans, g[cycle.size() - 1][i][j][k]);
				}
			}
			else{
				if(t == mt(0,1,L))if(g[cycle.size() - 1][i][j][k] != -1){
					ans = min(ans, g[cycle.size() - 1][i][j][k]);
				}
			}
		}
		
	}
	
	if(ans == 1e9)out(-1);
	else out(ans); 
	
}

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