제출 #1265496

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1265496		syanvu	Cat Exercise (JOI23_ho_t4)	C++20	31 / 100	2096 ms	43496 KiB

Main

#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp> 
// #include <ext/pb_ds/tree_policy.hpp>

#define SS ios_base::sync_with_stdio(0);cin.tie(nullptr);cout.tie(nullptr);
#pragma optimize("g", on)
#pragma GCC optimize("03")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx2,mmx,fma,avx,tune=native")
// #define int long long
#define all(x) x.begin(),x.end()
#define F first
#define S second


using namespace std;
// using namespace __gnu_pbds; 
// #define ordered_set tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>

const int LG = 20,N = 2e5+1,inf = 1e9,MOD = 998244353;
const double eps = 1e-9;
int T;

vector<int> g[N];
int h[N];
int block[N],dep[N],up[N][21],tin[N],tout[N],timer,dp[N];

void calc(int v,int p){
    tin[v]=++timer;
    up[v][0]=p;
    for(int i=1;i<=20;i++){
        up[v][i]=up[up[v][i-1]][i-1];
    }
    for(int to:g[v]){
        if(to==p) continue;
        dep[to]=dep[v]+1;
        calc(to,v);
    }
    tout[v]=timer;
}
bool ch(int u,int v){
    return (tin[u]<=tin[v] && tout[u]>=tout[v]);
}
int lca(int u,int v){
    if(ch(u,v)) return u;
    if(ch(v,u)) return v;
    for(int i=20;i>=0;i--){
        if(!ch(up[u][i],v)) u=up[u][i];
    }
    return up[u][0];
}

int get(int v,int p){
    int mx=v;
    for(int to:g[v]){
        if(block[to] || to==p) continue;
        int go=get(to,v);
        if(h[mx]<h[go]) mx=go;
    }
    return mx;
}
void dfs(int v,int p){
    int w=get(v,v);
    block[w]=1;
    int mx=0;
    for(int to:g[w]){
        if(to==p || block[to]) continue;
        dfs(to,w);
        mx=max(mx,dp[to]);
    }
    dp[v]=mx+dep[v]+dep[w]-2*dep[lca(v,w)]+1;
    // cout<<mx<<' '<<dp[v]<<' '<<w<<'\n';
}

void solve() {
    int n;
    cin>>n;
    int s=0;
    for(int i=1;i<=n;i++){
        cin>>h[i];
        if(h[i]==n) s=i;
    }
    for(int i=1;i<n;i++){
        int u,v;
        cin>>u>>v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    calc(s,s);
    int ans=0;
    block[s]=1;
    for(int to:g[s]){
        dfs(to,s);
        ans=max(ans,dp[to]);
    }
    cout<<ans;
    return;
}
signed main() {
    //   freopen("deleg.in","r",stdin);    
    // freopen("deleg.out","w",stdout);
    SS
    int t = 1;
    if (T) {
        cin >> t;
    }
    while (t--) {
        solve();
    }
}
/*
*/

• 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