2024牛客国庆集训派对day7

E Eyjafjalla

主席树二分加树上倍增

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define N 100005
int n;
int t[N];
vector<int>g[N];
vector<int> v;

int get_id(int x){ 
	return lower_bound(v.begin(),v.end(),x)  - v.begin() + 1;
}      
struct PresidentTree {
	int cntNodes, root[N];
	struct node {
		int l, r;
		int cnt;
	} tr[4 * N + 17 * N];
	void modify(int &u, int v, int l, int r, int x) {
		u = ++cntNodes;
		tr[u] = tr[v];
		tr[u].cnt++;
		if (l == r) return;
		int mid = (l + r) / 2;
		if (x <= mid)
			modify(tr[u].l, tr[v].l, l, mid, x);
		else
			modify(tr[u].r, tr[v].r, mid + 1, r, x);
	}
	int kth(int u, int v, int l, int r, int k) {
		if (l == r) return l;
		int res = tr[tr[v].l].cnt - tr[tr[u].l].cnt;
		int mid = (l + r) / 2;
		if (k <= res)
			return kth(tr[u].l, tr[v].l, l, mid, k);
		else
			return kth(tr[u].r, tr[v].r, mid + 1, r, k - res);
	}
}st;
int lg[N];
int val[N][32];
int dep[N];
int  l[N],r[N];
int id[N];
int cnt=0;
void dfs(int x,int fa){
	id[++cnt]=t[x];
	l[x]=cnt;
	val[x][0]=fa;
	dep[x]=dep[fa]+1;
	for(int i=1;i<=lg[dep[x]];i++){
		val[x][i]=val[val[x][i-1]][i-1];
	}
	for(int v:g[x]){
		if(v==fa) continue;
		dfs(v,x);
	}
	r[x]=cnt;
}
int find(int x,int r){
	for(int k=lg[dep[x]];k>=0;k--){
		if(t[val[x][k]]<=r){
			x=val[x][k];
		}
	}
	return x;
}
void solve(){
	cin>>n;
	for (int i = 1; i <= n; i++) { //预处理 log
		lg[i] = lg[i - 1] + (1 << lg[i - 1] == i);
	}
	for(int i=1;i<n;i++){
		int u,v;
		cin>>u>>v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	for(int i=1;i<=n;i++){
		cin>>t[i];
		v.push_back(t[i]);
	}
	sort(v.begin(),v.end());
	v.erase(unique(v.begin(),v.end()),v.end());
	t[0]=INT_MAX;
	dfs(1,0);
	for(int  i=1;i<=n;i++){
//		cout<<id[i]<<'\n';
		st.modify(st.root[i],st.root[i-1],1,n,get_id(id[i]));
	}
	int q;
	cin>>q;
	while(q--){
		int x,le,re;
		cin>>x>>le>>re;
		if(t[x]>=le&&t[x]<=re){
//			cout<<find(x,re)<<'\n';
			x=find(x,re);
			int sum=r[x]-l[x]+1;
			int ll=1,rr=sum;
			while(ll<=rr){
				int mid=(ll+rr)/2;
				int k=mid;
				if(v[st.kth(st.root[l[x]-1],st.root[r[x]],1,n,k)-1]<le){
					ll=mid+1;
				}
				else{
					rr=mid-1;
				}
			}
			cout<<sum-(ll-1)<<'\n';
		}
		else{
			cout<<0<<'\n';
		}
		
	}
}
signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
		solve();

} 

H Happy Number

模拟一下三进制即可

#include <bits/stdc++.h>
using namespace std;
#define int long long
int a[100];
//      1 2 3 11 12 13 21 22 23
int n;//2 3 6 22 23 26 32 33 36
void solve(){
	cin>>n;
	int i=0;
	while(n){
		n-=1;
		a[++i]=n%3+1;
		n/=3;
	}
	map<int,int>mp;
	mp[1]=2;
	mp[2]=3;
	mp[3]=6;
	for(int j=i;j>=1;j--){
		cout<<mp[a[j]];
	}
}
signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	int t=1;
//	cin>>t;
	while(t--){
		solve();
	}
}