796B - Find The Bone - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
int main() {
  int n,m,k,u,v,pos=1;
  cin>>n>>m>>k;
  set<int>hole;
  auto hh=hole.begin();
  while(m--) cin>>u,hh=hole.emplace_hint(hh,u);
  while(k--)
  {
      cin>>u>>v;
      if(hole.count(pos)==1) break;
      if(u==pos) pos=v;
      else if(v==pos) pos=u;
  }
  cout<<pos;
    return 0;
}