#include "secret.h" #include <iostream> using namespace std; const int N=1001; int val[N][N],n; void recur(int l,int r) { if(l==r)return; int mid=(l+r)/2; // comput [mid-1,mid] for(int i=mid-1;i>=l;i--) { if(val[i][mid]!=-1)continue; // cout<<"Prefix "<<val[i][i]<<' '<<val[i+1][mid]<<endl; val[i][mid]=Secret(val[i][i],val[i+1][mid]); } for(int i=mid+2;i<=r;i++) { if(val[mid+1][i]!=-1)continue; // cout<<"Suffix "<<val[mid+1][i-1]<<' '<<val[i][i]<<endl; val[mid+1][i]=Secret(val[i][i],val[mid+1][i-1]); } recur(l,mid); recur(mid+1,r); // cout<<"FUll "<<val[l][mid]<<' '<<val[mid+1][r]<<endl; // val[l][r]=Secret(val[l][mid], val[mid+1][r]); } void Init(int N, int A[]) { n=N; for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { val[i][j]=-1; } val[i][i]=A[i]; } recur(0,n-1); } int Query(int L, int R) { for(int i=L;i<R;i++) { if(val[L][i]!=-1 and val[i+1][R]!=-1) { return Secret(val[L][i], val[i+1][R]); } } return val[L][R]; }