Submission #545524

#	Time	Username	Problem	Language	Result	Execution time	Memory
545524		NaimSS	Mergers (JOI19_mergers)	C++14	100 / 100	919 ms	138516 KiB

mergers

#include <bits/stdc++.h>
#define ld long double
#define endl "\n"
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pb push_back
#define mp(a,b) make_pair(a,b)
#define ms(v,x) memset(v,x,sizeof(v))
#define all(v) v.begin(),v.end()
#define ff first
#define ss second
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define per(i, a, b) for(int i = b-1; i>=a ; i--)
#define trav(a, x) for(auto& a : x)
#define allin(a , x) for(auto a : x)
#define Unique(v) sort(all(v));v.erase(unique(all(v)),v.end());
#define sz(v) ((int)v.size())
using namespace std;
typedef vector<int> vi;
#define y1 abacaba
//#define left oooooopss
#define db(x) cerr << #x <<" == "<<x << endl;
#define db2(x,y) cerr<<#x <<" == "<<x<<", "<<#y<<" == "<<y<<endl;
#define db3(x,y,z) cerr << #x<<" == "<<x<<", "<<#y<<" == "<<y<<", "<<#z<<" == "<<z<<endl;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<ll> vl;
std::mt19937 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down
inline ll mod(ll n, ll m ){ ll ret = n%m; if(ret < 0) ret += m; return ret; }
ll gcd(ll a, ll b){return (b == 0LL ? a : gcd(b, a%b));}
ll exp(ll b,ll e,ll m){
  b%=m;
  ll ans = 1;
  for (; e; b = b * b % m, e /= 2)
      if (e & 1) ans = ans * b % m;
  return ans;
}
  
// debug:
void dbg_out() { cerr << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T){ 
  cerr << ' ' << H; 
  dbg_out(T...); 
}
#ifdef LOCAL
#define dbg(...) cerr<<"(" << #__VA_ARGS__<<"):" , dbg_out(__VA_ARGS__) , cerr << endl
#else
#define dbg(...) 42
#endif
//

const int N = 500100;
vi g[N];
int S[N];
int p[N];
int cnt[N];
int f(int x){return p[x] = (p[x]==x?x:f(p[x]));}
void join(int a,int b){
	p[f(a)]=f(b);
}

pii e[N];

void dfs(int v,int p,map<int,int>&mp){
	if(cnt[S[v]]!=1)
		mp[S[v]] = 1;
	for(auto to : g[v])if(to!=p){
		map<int,int> nv;
		dfs(to,v,nv);
		if(sz(nv) > sz(mp))mp.swap(nv);

		for(auto it : nv){
			mp[it.ff]+=it.ss;
			if(mp[it.ff] == cnt[it.ff]){
				// todo mundo na subarvore. Cor n importa mais
				mp.erase(it.ff);
			}
		}
	}
	if(mp.size()!=0 && p!=-1){
		// alguem não ta dentro.
		// pode juntar com o pai
		join(v,p);
	}
}
int deg[N];
int32_t main(){
    fastio;
	int n,k;
	cin >> n >> k;
	rep(i,0,n-1){
		int a,b;
		cin >> a >> b;
		g[a].pb(b);
		g[b].pb(a);
		e[i] = pii(a,b);
	}
	rep(i,1,n+1)p[i]=i;
	rep(i,1,n+1)cin >> S[i],cnt[S[i]]++;
	map<int,int> mp;
	dfs(1,0,mp);
	rep(i,0,n-1){
		if(f(e[i].ff)!=f(e[i].ss)){
			deg[f(e[i].ff)]++;
			deg[f(e[i].ss)]++;
		}
	}
	int res=0;
	set<int> used;
	rep(i,1,n+1)used.insert(f(i));

	for(int i : used)
		if(deg[i]<=1)res++;
	
	if(res<=1)res=0;
	cout << (res + 1)/2 << endl;


    // math -> gcd it all
    // Did u check N=1? Did you switch N,M?
}

• Subtask 1: 10 / 10
• Subtask 2: 24 / 24
• Subtask 3: 14 / 14
• Subtask 4: 22 / 22
• Subtask 5: 30 / 30