#include "secret.h"
#include <cassert>
const int lim=1100;
int n,*a;
int aa[15][lim];
void dnc(int l,int r,int dep=0){
if(l==r){
return;
}
int mid=(l+r)>>1;
aa[dep][mid]=a[mid];
for(int i=mid-1;l<=i;i--){
aa[dep][i]=Secret(a[i],aa[dep][i+1]);
}
aa[dep][mid+1]=a[mid+1];
for(int i=mid+2;i<=r;i++){
aa[dep][i]=Secret(aa[dep][i-1],a[i]);
}
dnc(l,mid,dep+1),dnc(mid+1,r,dep+1);
}
void Init(int N, int A[]) {
n=N;
a=A;
dnc(0,n-1);
}
int Query(int L, int R) {
if(L==R){
return a[L];
}
int l=0,r=n-1,dep=0;
while(l<=r){
int mid=(l+r)>>1;
if(L<=mid&&mid<R){
return Secret(aa[dep][L],aa[dep][R]);
}else if(mid+1==L){
return aa[dep][R];
}
else if(mid==R){
return aa[dep][L];
}else if(mid<L){
l=mid+1;
}else{
r=mid-1;
}
dep++;
}
return -1;
}
