#include <bits/stdc++.h> using namespace std; #define fi first #define se second #define pb push_back #define ll long long #define ld long double const int N=5e5+50; vector<int>E[N]; int n,K,col[N],Num[N]; int par[N],sajz[N]; bool active[N];int num[N]; map<int,int>mapa[N]; int numbad[N]; int root[N]; void DFS(int u,int p=0){ int v=0;sajz[u]=1;par[u]=p; for(auto i:E[u])if(i!=p){ DFS(i,u);num[u]+=num[i]; if(sajz[i]>sajz[v])v=i; sajz[u]+=sajz[i]; } root[u]=u; if(v>0)root[u]=root[v]; if(mapa[root[u]][col[u]]==0)numbad[root[u]]++; mapa[root[u]][col[u]]++; if(mapa[root[u]][col[u]]==Num[col[u]])numbad[root[u]]--; for(auto i:E[u])if(i!=p&&i!=v){ for(auto [x,y]:mapa[root[i]]){ if(mapa[root[u]][x]==0)numbad[root[u]]++; mapa[root[u]][x]+=y; if(mapa[root[u]][x]==Num[x])numbad[root[u]]--; } } if(p>0&&numbad[root[u]]==0)active[u]=active[p]=true; num[u]+=active[u]; } int main(){ scanf("%i%i",&n,&K); for(int i=1;i<n;i++){ int u,v;scanf("%i%i",&u,&v); E[u].pb(v),E[v].pb(u); } for(int i=1;i<=n;i++)scanf("%i",&col[i]),Num[col[i]]++; DFS(1); int ct=0; for(int i=1;i<=n;i++)ct+=active[i]; int res=0; for(int i=1;i<=n;i++)if(active[i]){ if(num[i]==1)res++; else if(num[i]==ct){ bool moze=true; for(auto j:E[i])if(j!=par[i]){ if(0<num[j]&&num[j]<ct-1) moze=false; } if(moze) res++; } } res=res+1>>1; printf("%i\n",res); return 0; }

mergers.cpp: In function 'int main()':
mergers.cpp:39:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |     scanf("%i%i",&n,&K);
      |     ~~~~~^~~~~~~~~~~~~~
mergers.cpp:41:22: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         int u,v;scanf("%i%i",&u,&v);
      |                 ~~~~~^~~~~~~~~~~~~~
mergers.cpp:44:31: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |     for(int i=1;i<=n;i++)scanf("%i",&col[i]),Num[col[i]]++;
      |                          ~~~~~^~~~~~~~~~~~~~