Submission #526051

#	Time	Username	Problem	Language	Result	Execution time	Memory
526051		BackNoob	Logičari (COCI21_logicari)	C++14	110 / 110	225 ms	46208 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define endl '\n'
#define MASK(i) (1LL << (i))
#define ull unsigned long long
#define ld long double
#define pb push_back
#define all(x) (x).begin() , (x).end()
#define BIT(x , i) ((x >> (i)) & 1) 
#define TASK "task"
#define sz(s) (int) (s).size()

using namespace std;
const int mxN = 3e5 + 227;
const int inf = 1e9 + 277;
const int mod = 1e9 + 7;
const ll infll = 1e18 + 7;
const int base = 307;
const int LOG = 20;
 
template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}

struct DSU{
	vector<int> lab;
	DSU(){}
	DSU(int _n)
	{
		lab.resize(_n + 7 , -1);
	}
	int root(int u) {return lab[u] < 0 ? u : lab[u] = root(lab[u]);};
	bool union_root(int u , int v)
	{
		u = root(u);
		v = root(v);
		if(u == v) return false;
		if(lab[u] > lab[v]) swap(u , v);
		lab[u] += lab[v];
		lab[v] = u;
		return true;
	}
} dsu;

int n;
vector<int> adj[mxN];
pair<int , int> edges[mxN];
bool marked[mxN];
int root;
int spec;
int dp[mxN][2][2][2][2];
int par[mxN];

void dfs(int u , int pa)
{
	for(int v : adj[u]) {
		if(v == pa) continue;
		par[v] = u;
		dfs(v , u);
	}
}

int sol(int u , int now , int pr , int c1 , int c2)
{
	if(u == root && now != c1) return inf;
	if(u == spec && now != c2) return inf;
	if(u == spec && pr == true && c1 == true) return inf;

	int &res = dp[u][now][pr][c1][c2];
	if(res != -1) return res;
	res = inf;

	bool ok = false;
	if(pr == true) ok = true;
	if(u == root && c2 == true) ok = true;
	if(u == spec && c1 == true) ok = true;

	ll f1 = now;
	ll f2 = inf;

	for(int v : adj[u]) {
		if(v == par[u]) continue;
		f1 += sol(v , 0 , now , c1 , c2);
		f2 = min(f2 , 1LL * sol(v , 1 , now , c1 , c2) - sol(v , 0 , now , c1 , c2));
	}

	if(ok == true) minimize(res , f1);
	else minimize(res , f1 + f2);
	return res;

}

void solve()
{
	cin >> n;
	for(int i = 1 ; i <= n ; i++) cin >> edges[i].fi >> edges[i].se;

	dsu = DSU(n);
	for(int i = 1 ; i <= n ; i++) {
		if(dsu.union_root(edges[i].fi , edges[i].se) == true) {
			marked[i] = true;
			adj[edges[i].fi].pb(edges[i].se);
			adj[edges[i].se].pb(edges[i].fi);
		}
	}

	for(int i = 1 ; i <= n ; i++) {
		if(marked[i] == false) {
			root = edges[i].fi;
			spec = edges[i].se;
		}
	}

	dfs(root , -1);
	memset(dp , -1 , sizeof(dp));

	int ans = inf;
	for(int c1 = 0 ; c1 <= 1 ; c1++)
	for(int c2 = 0 ; c2 <= 1 ; c2++) minimize(ans , sol(root , c1 , 0 , c1 , c2));

	if(ans == inf) cout << -1;
	else cout << ans;
}
 
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    //freopen(TASK".in" , "r" , stdin);
    //freopen(TASK".out" , "w" , stdout);
    
    int tc = 1;
    //cin >> tc;
    while(tc--) {
    	solve();
    }
    return 0;
}

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