Submission #7489524

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Source Code Expand

#define DEB

#include<bits/stdc++.h>
#include<unistd.h>
#define REP(i,m) for(int i=0;i<(m);++i)
#define REPN(i,m,in) for(int i=(in);i<(m);++i)
#define ALL(t) (t).begin(),(t).end()
#define CLR(a) memset((a),0,sizeof(a))
#define pb push_back
#define mp make_pair
#define fr first
#define sc second

using namespace std;


#ifdef DEB
#define dump(x)  cerr << #x << " = " << (x) << endl
#define prl cerr<<"called:"<< __LINE__<<endl
template<class T> void debug(T a,T b){ for(;a!=b;++a) cerr<<*a<<' ';cerr<<endl;}
#else
#define dump(x) ;
#define prl ;
template<class T> void debug(T a,T b){ ;}
#endif

template<class T> void chmin(T& a,const T& b) { if(a>b) a=b; }
template<class T> void chmax(T& a,const T& b) { if(a<b) a=b; }

typedef long long int lint;
typedef pair<int,int> pi;

namespace std{
  template<class S,class T>
  ostream &operator <<(ostream& out,const pair<S,T>& a){
    out<<'('<<a.fr<<','<<a.sc<<')';
    return out;
  }
}
int L=36;
const lint INF=1e18;

lint H=(1<<18);
lint a,b,x;


pair<lint,int> baby[1<<18];
lint solve(){
  cin>>a>>b>>x;
  if(a==x) return 0;
  
  lint res=0;
  while(L>0 && !(b>>(L-1)&1)){
    if(a==x) return res;

    if(x>>(L-1)&1) return -1;
    if(a>>(L-1)&1){
      a=(a/2)^((a&1)*b);
      ++res;
    }
    --L;
  }
  H = 1 << (L / 2);
  if(a==x) return res;

  lint conv_H[36]={0};

  REP(i,L){
    lint cur=(1ll<<i);
    REP(j,H){
      cur=(cur/2)^((cur&1)*b);
    }
    conv_H[i]=cur;
  }

  
  lint cur=x;
  REP(i,H){
    baby[i]=mp(cur,i);
    cur=(cur/2)^((cur&1)*b);
  }
  sort(baby,baby+H);
  
  
  lint ans=INF;
  
  cur=a;
  REP(i,H){
    lint c=0;
    REP(j,L) if(cur>>j&1) c^=conv_H[j];

    int pos=lower_bound(baby,baby+H,mp(c+1,-1))-baby;
    --pos;
    if(pos>=0 && baby[pos].fr==c) chmin(ans,H*(i+1)-baby[pos].sc);

    cur=c;
  }
  if(ans==INF) return -1;
  return ans+res;
}



int main(){
  printf("%lld\n",solve());
  return 0;

}

Submission Info

Judge Result