Submission #1063813

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063813		imarn	Cat Exercise (JOI23_ho_t4)	C++14	100 / 100	128 ms	41136 KiB

Main

#include<bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("avx2")
#define ll long long
#define pii pair<ll,ll>
#define pll pair<ll,ll>
#define plx pair<ll,int>
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(),x.end()
#define vi vector<int>
#define vl vector<ll>
#define vvi vector<vi>
using namespace std;
const int mxn=2e5+5;
vector<int>g[mxn];
int pr[mxn]{0},h[mxn]{0},up[mxn][20]{0},d[mxn]{0};
void dfs(int u,int p){
    up[u][0]=p;
    for(int i=1;i<20;i++)up[u][i]=up[up[u][i-1]][i-1];
    for(auto v:g[u]){
        if(v==p)continue;
        d[v]=d[u]+1;dfs(v,u);
    }
}
int get(int r){
    return pr[r]==r?r:pr[r]=get(pr[r]);
}
int lca(int a,int b){
    if(d[b]<d[a])swap(a,b);
    for(int i=19;i>=0;i--)if(d[b]-(1<<i)>=d[a])b=up[b][i];
    if(a==b)return a;
    for(int i=19;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 d[a]+d[b]-2*d[lca(a,b)];
}
ll dp[mxn]{0};
int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    int n;cin>>n;iota(pr,pr+n+1,0);
    for(int i=1;i<=n;i++)cin>>h[i];
    for(int i=1;i<=n-1;i++){
        int a,b;cin>>a>>b;
        g[h[a]].pb(h[b]);g[h[b]].pb(h[a]);
    }dfs(1,1);
    for(int i=1;i<=n;i++){
        for(auto v:g[i]){
            int vv=get(v);
            if(vv<i){
                dp[i]=max(dp[i],dp[vv]+cal(i,vv));
                pr[vv]=i;
            }
        }
    }cout<<dp[n];
}

• 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