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  1. #include <bits/stdc++.h>
  2. #define fi first
  3. #define se second
  4. #define all(v) v.begin() , v.end()
  5. #define sz(v) int(v.size())
  6. #define unq(v) sort(all(v)); v.resize(unique(all(v)) - v.begin());
  7. using namespace std;
  8.  
  9. typedef long long ll;
  10. typedef pair<int , int> ii;
  11. typedef pair<long long , int> lli;
  12.  
  13. const int maxN = int(3e5)+7;
  14.  
  15. struct node{
  16.     int n , sz[maxN];
  17.     ll dp[maxN] , cost = 0;
  18.     int ver = -1;
  19.     vector<int> g[maxN];
  20.     vector<ii> E;
  21.  
  22.     void init(int _n){
  23.         n = _n;
  24.         cost = 0;
  25.         ver = -1;
  26.         for (int i = 1 ; i <= n ; i++){
  27.             g[i].clear();
  28.             dp[i] = 0;
  29.         }
  30.         E.clear();
  31.     }
  32.  
  33.     void add_edge(int u , int v){
  34.         g[u].push_back(v);
  35.         g[v].push_back(u);
  36.         E.push_back({u , v});
  37.     }
  38.  
  39.     void dfs_init(int u , int par){
  40.         sz[u] = 1;
  41.         dp[u] = 0;
  42.         for (int v : g[u]){
  43.             if (v != par){
  44.                 dfs_init(v , u);
  45.                 sz[u] += sz[v];
  46.                 dp[u] += dp[v] + 1ll * sz[v];
  47.             }
  48.         }
  49.     }
  50.  
  51.     void change(int u , int v){
  52.         sz[u] -= sz[v];
  53.         dp[u] -= dp[v] + 1ll * sz[v];
  54.         sz[v] += sz[u];
  55.         dp[v] += dp[u] + 1ll * sz[u];
  56.     }
  57.  
  58.     void dfs_reroot(int u , int par){
  59.         cost += dp[u];
  60.         if (ver == -1 || dp[ver] < dp[u]) ver = u;
  61.         for (int v : g[u]){
  62.             if (v != par){
  63.                 change(u , v);
  64.                 dfs_reroot(v , u);
  65.                 change(v , u);
  66.             }
  67.         }
  68.     }
  69. } f[3];
  70.  
  71. node add(node X , node Y){
  72.     int n = X.n + Y.n;
  73.     node ans; ans.init(n);
  74.     for (auto it : X.E){
  75.         ans.add_edge(it.fi , it.se);
  76.     }
  77.     for (auto it : Y.E){
  78.         ans.add_edge(it.fi + X.n , it.se + X.n);
  79.     }
  80.     ans.add_edge(X.ver , Y.ver + X.n);
  81.     ans.dfs_init(1 , 0);
  82.     ans.dfs_reroot(1 , 0);
  83.     return ans;
  84. }
  85.  
  86. void solve(){
  87.     for (int i = 0 ; i < 3 ; i++){
  88.         int n; cin >> n;
  89.         f[i].init(n);
  90.         for (int j = 1 ; j < n ; j++){
  91.             int u , v;
  92.             cin >> u >> v;
  93.             f[i].add_edge(u , v);
  94.         }
  95.         f[i].dfs_init(1 , 0);
  96.         f[i].dfs_reroot(1 , 0);
  97.     }
  98.     node A = add(add(f[0] , f[1]) , f[2]);
  99.     node B = add(add(f[1] , f[2]) , f[0]);
  100.     node C = add(add(f[2] , f[0]) , f[1]);
  101.     cout << max(A.cost , max(B.cost , C.cost)) / 2 << "\n";
  102. }
  103.  
  104. #define name "A"
  105.  
  106. int main(){
  107.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  108.     if (fopen(name".INP" , "r")){
  109.         freopen(name".INP" , "r" , stdin);
  110.         freopen(name".OUT" , "w" , stdout);
  111.     }
  112.     int t = 1; cin >> t;
  113.     solve();
  114.     return 0;
  115. }
  116.  
  117.  
  118.  
Success #stdin #stdout 0.05s 104904KB
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https://ideone.com/qlHwcC
language:
C++14 (gcc 8.3)
created:
4 days ago
visibility:
public

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