Submission #847812

#	Time	Username	Problem	Language	Result	Execution time	Memory
847812		8pete8	Cat Exercise (JOI23_ho_t4)	C++17	100 / 100	212 ms	88760 KiB

Main

#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<unordered_map>
#include <queue>
#include<cstring>
#include<algorithm>
#include<limits.h>
#include<cmath>
using namespace std;
#define ll long long
#define f first
#define endl "\n"
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define pll pair<ll,ll>
#define pb push_back
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#define int long long
#define double long double
#define mod 1000000007
const int mxn=2*1e5,lg=25;
int pa[mxn+10],n;
vector<int>adj[mxn+10];
int he[mxn+10],h[mxn+10],up[mxn+10][lg+10];
void dfs(int cur,int p){
    for(auto i:adj[cur]){
        if(i==p)continue;
        up[i][0]=cur;
        h[i]=h[cur]+1;
        dfs(i,cur);
    }
}
int lca(int a,int b){
    if(h[a]<h[b])swap(a,b);
    int k=h[a]-h[b];
    for(int i=0;i<=lg;i++)if(k&(1<<i))a=up[a][i];
    if(a==b)return a;
    for(int i=lg;i>=0;i--){
        if(up[a][i]!=up[b][i]){
            a=up[a][i];
            b=up[b][i];
        }
    }
    return up[a][0];
}
int cal(int a,int b){
    return h[a]+h[b]-(2*h[lca(a,b)]);
}
int find(int u){
    if(pa[u]==u)return u;
    return pa[u]=find(pa[u]);
}
int dp[mxn+10];//max
int32_t main(){
    fastio
    cin>>n;
    for(int i=1;i<=n;i++){
        int a;cin>>a;
        he[i]=a;
        pa[i]=i;
    }
    for(int i=0;i<n-1;i++){
        int a,b;cin>>a>>b;
        adj[he[a]].pb(he[b]);//id by height
        adj[he[b]].pb(he[a]);
    }
    dfs(n,-1);
    for(int i=1;i<=lg;i++)for(int j=1;j<=n;j++)up[j][i]=up[up[j][i-1]][i-1];
    for(int i=1;i<=n;i++){
        for(auto j:adj[i]){
            int c=find(j);
            if(c<i){
                dp[i]=max(dp[i],dp[c]+cal(i,c));
                pa[c]=i;
            }
        }
    }
    cout<<dp[n];
    return 0;
}

• 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