結果

問題 No.364 門松木
ユーザー fumofumofuni
提出日時 2022-09-04 14:20:17
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 70 ms / 3,000 ms
コード長 2,603 bytes
コンパイル時間 2,258 ms
コンパイル使用メモリ 213,148 KB
最終ジャッジ日時 2025-02-07 02:38:04
ジャッジサーバーID
（参考情報） 		judge5 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 31
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3")
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,1,0,-1,1,-1,1,-1,0};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}
ll n;
vl a(5e4+10);
vvl g(5e4+10);
ll ans=0;
ll dfs(ll v,ll par=-1){
  vpl pls;//{value,index}
  for(auto p:g[v]){
    if(p==par)continue;
    ll f=dfs(p,v);
    pls.emplace_back(make_pair(f,p));
  }
  sort(all(pls));rev(all(pls));
  ll upscore=0,updeg=0;
  set<ll> seen;
  for(auto [value,idx]:pls){
    if(a[idx]<=a[v])continue;
    if(seen.count(a[idx]))continue;
    if(value<0)continue;
    seen.insert(a[idx]);
    upscore+=value;updeg++;
  }
  ll downscore=0,downdeg=0;
  seen.clear();
  for(auto [value,idx]:pls){
    if(a[idx]>=a[v])continue;
    if(seen.count(a[idx]))continue;
    if(value<0)continue;
    seen.insert(a[idx]);
    downscore+=value;downdeg++;
  }
  chmax(ans,upscore+updeg*(updeg-1));
  chmax(ans,downscore+downdeg*(downdeg-1));
  //上への遷移
  if(v==0)return 0;
  if(a[par]==a[v])return -INF;
  upscore=0,updeg=1;
  seen.clear();
  for(auto [value,idx]:pls){
    if(a[idx]<=a[v])continue;
    if(a[idx]==a[par])continue;
    if(seen.count(a[idx]))continue;
    if(value<0)continue;
    seen.insert(a[idx]);
    upscore+=value;updeg++;
  }
  downscore=0,downdeg=1;
  seen.clear();
  for(auto [value,idx]:pls){
    if(a[idx]>=a[v])continue;
    if(a[idx]==a[par])continue;
    if(seen.count(a[idx]))continue;
    if(value<0)continue;
    seen.insert(a[idx]);
    downscore+=value;downdeg++;
  }
  if(a[par]<a[v]){
    return downscore+downdeg*(downdeg-1);
  }
  else{
    return upscore+updeg*(updeg-1);
  }
}
int main(){
  cin >> n;
  rep(i,n)cin >> a[i];
  rep(i,n-1){
    ll x,y;cin >> x >> y;x--;y--;
    g[x].emplace_back(y);
    g[y].emplace_back(x);
  }
  dfs(0,-1);
  cout << ans/2 << endl;
}
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