Submission #1293425

#	Time	Username	Problem	Language	Result	Execution time	Memory
1293425		yf_yusuf	Cat Exercise (JOI23_ho_t4)	C++20	100 / 100	242 ms	67656 KiB

Main

//```//    YF YUSUF
// #include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <cmath>
#include <numeric>
#include <queue>
#include <stack>
#include <cassert>
#include <climits>
#include <string>
#include <cstdlib>
#include <random>
#include <iomanip>
#include <ctime>
using namespace std;
#ifdef YF_CHECK
	bool LOCAL = 1;
#else
	#pragma GCC optimize ("unroll-loops")
	#pragma GCC optimize ("inline")
	#pragma GCC optimize ("Ofast")
	#pragma GCC optimize ("O3")
	bool LOCAL = 0;
#endif
using i128 = __int128;
using ll   = long long;
using ld   = long double;
using vll  = vector <ll>;
using mll  = map <ll,ll>;
using pll  = pair <ll,ll>;
using vvl  = vector <vll>;
using vpll = vector <pll>;
template<class T>T MIN(T&a,T b){a=min(a,b);return a;}
template<class T>T MAX(T&a,T b){a=max(a,b);return a;}
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define sgr v+v+1,(tl+tr)/2+1,tr
#define sgl v+v,tl,(tl+tr)/2
#define pb push_back
#define ins insert
#define S second
#define F first
mt19937_64 MT(time(0));
ll BP(ll a,ll b,ll mod=1e9+7){
	if(b==0)return 1;
	ll q=BP(a,b/2,mod);
	return ((q*q)%mod*(b%2?a:1ll))%mod;
}
ll f(ll x){return x*(x+1)/2;}
ll dup(ll a,ll b){return (a+b-1)/b;}
ll lcm(ll a,ll b){return a/__gcd(a,b)*b;}
ll invf(ll x){return (-1+sqrt(1+8*x))/2;}
ll lg(ll x){return (x ? 63 - __builtin_clzll(x) : -1);}
const ll  mod=998244353;
const ll  INF=1e18;
const ll  inf=1e9+7;
const ll  N  =2e5+7;
ll n;
ll p[N], a[N];
vll g[N];

struct DSU{
	vll p,sz,mx;
	ll n;
	DSU(ll n):n(n){
		p.resize(n+1,0);
		sz.resize(n+1,1);
		mx.resize(n+1,1);
		for(int i=1;i<=n;i++){
			p[i] = i;
			mx[i] = i;
		}
	}
	ll get_mx(ll x){
		x = get(x);
		return mx[x];
	}
	ll get(ll x){
		if(p[x]==x)
			return x;
		else 
			return p[x] = get(p[x]);
	}
	bool up(ll a,ll b){
		ll A = a, B = b;
		a = get(a);
		b = get(b);
		if(a==b)return 0;
		if(sz[a] < sz[b])swap(a,b);
		p[b] = a;
		MAX(mx[a], mx[b]);
		sz[a] += sz[b];
		sz[b] = 0;
		return 1;
	}
};
ll timer, tin[N], tout[N];
ll up[20][N], d[N];
void pre_calc(ll v,ll p){
	tin[v] = ++timer;
	for(auto to : g[v])if(to != p){
		d[to] = d[v] + 1;
		up[0][to] = v;
		for(int j=1;j<20;j++)
			up[j][to] = up[j-1][up[j-1][to]];
		pre_calc(to, v);
	}
	tout[v] = ++timer;
}
bool check(ll a,ll b){
	return (tin[a] <= tin[b] && tout[b] <= tout[a]);
}
ll LCA(ll a,ll b){
	if(check(a, b))return a;
	if(check(b, a))return b;
	for(int j=19;j>=0;j--){
		ll u = up[j][a];
		if(!u || check(u, b))continue;
		a = u;
	}
	return up[0][a];
}
ll dist(ll a,ll b){
	ll c = LCA(a, b);
	return d[a] + d[b] - 2*d[c];
}
void YF_MAIN(ll TEST){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		p[a[i]] = i;
	}
	for(int i=1;i<n;i++){
		ll v, u;
		cin>>u>>v;
		g[u].pb(v);
		g[v].pb(u);
	}
	DSU dsu(n);
	for(int i=1;i<=n;i++)dsu.mx[i] = a[i];
	pre_calc(1, 1);
	
	// for(int i=1;i<=n;i++){
		// for(int j=1;j<i;j++){
			// cout<<i<<" "<<j<<" "<<dist(i, j)<<" q\n";
		// }
	// }
	
	ll dp[n+1]{};
	for(int v=1; v<=n; v++){
		ll i = p[v];
		for(auto j : g[i]){
			ll to = dsu.get_mx(j);
			// cout<<v<<" "<<to<<" :\n";
			if(to > v)continue;
			MAX(dp[v], dp[to] + dist(p[v], p[to]));
// cout<<v<<" "<<to<<", "<<dp[v]<<" "<<dp[to]<<", "<<i<<" "<<j<<", "<<dist(p[v], p[to])<<"\n";
			dsu.up(i, j);
		}
	}
	cout<<dp[n];
}
const bool TECT=0;
const bool FLSH=1;
const ll SN=1e0 + 7; ll SM[SN];
const ll FN=1e0 + 7; ll FACT[FN], inv[FN], FMOD=inf;
ll PER(ll n,ll k){return FACT[n] *inv[n-k]%FMOD;}
ll CNK(ll n,ll k){return PER(n,k)*inv[k  ]%FMOD;}
void BEFORE(){
	for(ll i=2;i<SN;i++){
		if(SM[i])continue;
		for(ll j=i;j<SN;j+=i)
			MAX(SM[j],i);
	}
	FACT[0]=inv[0]=1;
	for(int i=1;i<FN;i++){
		FACT[i]=FACT[i-1]*i%FMOD;
		inv[i]=BP(FACT[i],FMOD-2,FMOD);
	}
}
signed main(){
	// freopen(("input.txt"),"r",stdin);freopen(("output.txt"),"w",stdout);
	if(FLSH){
		ios_base::sync_with_stdio(0);
		cout.setf(ios::fixed);
		cout.precision(0);
		cout.tie(0);
		cin.tie(0);
	}
	cout<<(0 && LOCAL ? "\nYF_OUTPUT:\n\n" : "");
	int TEST=1;
	if(TECT)
		cin>>TEST;
	BEFORE();
	for(int T=1;T<=TEST;T++){
		// cout<<"Case "<<T<<": ";
		YF_MAIN(T);
		cout<<(T==TEST ? "" : "\n");
		cout<<flush;
	}
	return 0;
} 
//   YF YUSUF ```

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 23 / 23
• Subtask 7: 26 / 26