Submission #414116

#	Time	Username	Problem	Language	Result	Execution time	Memory
414116		nathanlee726	Mergers (JOI19_mergers)	C++14	24 / 100	211 ms	89856 KiB

mergers

//#include<i_am_noob_orz>
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define ll long long
#define int ll
#define ull unsigned long long
#define pii pair<int,int>
#define X first
#define Y second
#define mod ((ll)1e9+7)
#define pb push_back
#define mp make_pair
#define abs(x) ((x)>0?(x):(-(x)))
#define F(n) Fi(i,n)
#define Fi(i,n) Fl(i,0,n)
#define Fl(i,l,n) for(int i=l;i<n;i++)
#define memres(a) memset(a,0,sizeof(a))
#define all(a) a.begin(),a.end()
#define sz(a) ((int)a.size())
#define ceiling(a,b) (((a)+(b)-1)/(b))
#define endl '\n'
#define bit_count(x) __builtin_popcountll((x))
#define ykh mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define jimmy_is_kind false
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> rbtree;
 
//#define LOCAL
#ifdef LOCAL
#define bug(...) cerr<<"#"<<__LINE__<<' '<<#__VA_ARGS__<<"- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr<<x<<", "; _do(y...);}
#define IOS()
#else
#define IOS() ios_base::sync_with_stdio(0), cin.tie(0)
#define endl '\n'
#define bug(...)
#endif
 
int add(int a,int b){return(a+b>=mod?a+b-mod:a+b);}
int sub(int a,int b){return(a<b?a+mod-b:a-b);}
int po(int a,int b){
	if(b==0)return 1;
	if(b==1)return(a%mod);
	int tem=po(a,b/2);
	if(b&1)return(((tem*tem)%mod)*a)%mod;
	else return(tem*tem)%mod; 
}
int GCD(int a,int b){
	int x=0;
	int ra,rb;
	while(a&&b){
		if(((a&1)==0)&&((b&1)==0)){
			a>>=1,b>>=1,x++;
		}
		else if((a^b)&1){
			if(a&1)b>>=1;
			else a>>=1;
		}
		else{
			ra=abs(a-b),rb=min(a,b);
			a=ra,b=rb;
		}
	}
	return max(a,b)<<x;
}
int gcd(int a,int b){if(b==0)return a;return gcd(b,a%b);}
vector<int> g[500010],la[500010],gr[500010];
int di[500010],st[500010],pa[500010],fr[500010],si[500010],fa[500010],ct[500010],ind=0,l[500010],r[500010],ST[1000010][20],id[1000010],ct2[500010];
int find(int x){ 
	if(fr[x]!=x)fr[x]=find(fr[x]);
	return fr[x];
} 
void merge(int x,int y){
	x=find(x),y=find(y);
	if(x==y)return;
	if(si[x]>si[y])swap(x,y);
	fr[x]=y;
	si[y]+=si[x];
}
void dfs1(int p,int f,int d){
	id[ind]=p;
	di[p]=d;
	l[p]=ind++;
	for(int u:g[p]){
		if(u==f)continue;
		dfs1(u,p,d+1);
	}
	id[ind]=p;
	r[p]=ind++;
}
void dfs(int p,int f,int d){
	fa[p]=f;
	pa[p]=d-la[st[p]].back();
	la[st[p]].pb(d);
	for(int u:g[p]){
		if(u==f)continue;
		dfs(u,p,d+1);
	}
	la[st[p]].pop_back(); 
}
void dfs2(int p,int f){
	for(int u:g[p]){
		if(u==f)continue;
		if(find(p)!=find(u))ct2[find(p)]++,ct2[find(u)]++;
		dfs2(u,p);
	}
} 
int LCA(int x,int y){
	int li=min(l[x],l[y]),ri=max(r[x],r[y]);
	bug(li,ri);
	int len=ri-li+1;
	int lg=__lg(len);
	return (di[ST[li][lg]]<di[ST[ri-(1<<lg)+1][lg]]?ST[li][lg]:ST[ri-(1<<lg)+1][lg]);
}
signed main(){
	IOS();
	int n,k;
	cin>>n>>k;
	if(n==1){
		cout<<"0"<<endl;
		return 0;
	}
	F(n-1){
		int x,y;
		cin>>x>>y;
		--x,--y;
		g[x].pb(y);
		g[y].pb(x);
	}
	F(n)cin>>st[i];
	F(n){
		gr[st[i]].pb(i);
	}
	dfs1(0,-1,1);
	F(2*n)ST[i][0]=id[i];
	Fi(j,19)for(int i=0;i+(1<<(j+1))-1<2*n;i++){
		ST[i][j+1]=(di[ST[i][j]]<di[ST[i+(1<<j)][j]]?ST[i][j]:ST[i+(1<<j)][j]);
	}
	F(k){
		int np=gr[i+1][0];
		Fi(j,sz(gr[i+1])-1){
			np=LCA(np,gr[i+1][j+1]);
		}	
		la[i+1].pb(di[np]);
	}
	dfs(0,-1,1);
	F(n)fr[i]=i,si[i]=1,ct[i]=sz(g[i]);
	F(k){
		if(sz(gr[i+1])>=2){
			Fi(j,sz(gr[i+1])-1){
				merge(gr[i+1][j],gr[i+1][j+1]);
			}
		}
	}
	queue<pii> q;
	F(n){
		if(sz(g[i])==1&&i!=0){
			q.push({i,pa[i]});
		}
	}
	while(!q.empty()){
		pii tmp=q.front();q.pop();
		if(tmp.Y>0)merge(tmp.X,fa[tmp.X]);
		tmp.X=fa[tmp.X];
		tmp.Y=max(pa[tmp.X],tmp.Y-1);
		if(tmp.X!=-1){
			ct[tmp.X]--;
			pa[tmp.X]=max(tmp.Y,pa[tmp.X]);
			if(ct[tmp.X]==1)q.push(tmp); 
		} 
	}
	dfs2(0,-1);
	int ans=0;
	F(n){
		bug(pa[i]);
		if(ct2[i]==1)ans++;
	}
	ans=ceiling(ans,2);
	cout<<ans<<endl;
	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 24
• Subtask 3: 14 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30