Submission #930675

#	Time	Username	Problem	Language	Result	Execution time	Memory
930675		Xiaoyang	Cat Exercise (JOI23_ho_t4)	C++17	31 / 100	219 ms	249384 KiB

Main

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
 
#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 1ll<<60
#define rep(i,a,b) for (ll i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
#define endl "\n"
void inc(ll &a,ll b) {a=(a+b)%mod;}
void dec(ll &a,ll b) {a=(a-b+mod)%mod;}
int prod(ll a,ll b) {return ll(a)*ll(b)%mod;}
int lowbit(ll x) {return x&(-x);}
ll p0w(ll base,ll p) {ll ret=1;while(p>0){if (p%2ll==1ll) ret=ret*base%mod;base=base*base%mod;p/=2ll;}return ret;}



const ll maxn=5555;
vector<ll>alist[maxn];
ll p[maxn],blocked[maxn];
ll dp[maxn];

ll dfs(ll u,ll fa){
	blocked[u]=1;
	ll tmp=0;
	for(auto x:alist[u]){
		if(x==fa)continue;
		if(blocked[x])continue;
		ll mx=x;
		bool vis[maxn];
		memset(vis,0,sizeof vis);
		vis[x]=1;
		ll dis[maxn];
		memset(dis,0,sizeof dis);
		dis[x]=1;
		queue<ll>q;
		q.push(x);
		while(!q.empty()){
			ll uu=q.front();
			q.pop();
			for(auto xx:alist[uu]){
				if(blocked[xx])continue;
				if(vis[xx])continue;
				if(p[xx]>p[mx])mx=xx;
				dis[xx]=dis[uu]+1;
				vis[xx]=1;
				q.push(xx);
			}
		}
		//rep(i,1,10)cout<<dis[i]<<" ";
		//cout<<endl;
		//debug(mx);
		tmp=max(tmp,dfs(mx,-1)+dis[mx]);
	}
	return dp[u]=tmp;
}

signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	ll n;cin>>n;
	rep(i,1,n+1)cin>>p[i];
	rep(i,1,n){
		ll a,b;cin>>a>>b;
		alist[a].pb(b);
		alist[b].pb(a);
	}
	ll st=0;
	rep(i,1,n+1){
		if(p[i]>p[st])st=i;
	}
	memset(dp,0,sizeof dp);
	cout<<dfs(st,-1)<<endl;
	return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 10 / 10
• Subtask 5: 0 / 20
• Subtask 6: 0 / 23
• Subtask 7: 0 / 26