Submission #792631

#	Time	Username	Problem	Language	Result	Execution time	Memory
792631		Theo830	Cat Exercise (JOI23_ho_t4)	C++17	31 / 100	2101 ms	881928 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e9+7;
const ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ll,ii>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
ll n;
ll p[200005];
vector<vll>adj;
ll dp[200005];
ll solve(ll idx){
    if(dp[idx] != -1){
        return dp[idx];
    }
    ll ans = 0;
    queue<ll>q;
    ll dist[n+5];
    memset(dist,-1,sizeof dist);
    dist[idx] = 0;
    q.push(idx);
    while(!q.empty()){
        ll f = q.front();
        q.pop();
        for(auto x:adj[f]){
            if(dist[x] == -1 && p[x] < p[idx]){
                q.push(x);
                dist[x] = dist[f] + 1;
                ans = max(ans,dist[x] + solve(x));
            }
        }
    }
    return dp[idx] = ans;
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin>>n;
    adj.assign(n+5,vll());
    ll root = -1;
    f(i,0,n){
        cin>>p[i+1];
        if(p[i+1] == n){
            root = i+1;
        }
    }
    f(i,0,n-1){
        ll a,b;
        cin>>a>>b;
        adj[a].pb(b);
        adj[b].pb(a);
    }
    memset(dp,-1,sizeof dp);
    cout<<solve(root)<<"\n";
}

• 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