#include "secret.h"
const int MAXN = 1000, LG = 10;
int a[MAXN];
int memo[LG][MAXN], mask[MAXN];
void DnC(int l, int r, int depth) {
if (l >= r) return;
int m = (l + r) / 2;
memo[depth][m] = a[m];
for (int i = m - 1; i >= l; i--) {
memo[depth][i] = Secret(a[i], memo[depth][i + 1]);
}
memo[depth][m + 1] = a[m + 1];
for (int i = m + 2; i <= r; i++) {
memo[depth][i] = Secret(memo[depth][i - 1], a[i]);
}
for (int i = m + 1; i <= r; i++) mask[i] ^= 1 << depth;
DnC(l, m, depth + 1);
DnC(m + 1, r, depth + 1);
}
void Init(int N, int A[]) {
for (int i = 0; i < N; i++) a[i] = A[i];
DnC(0, N - 1, 0);
}
int Query(int L, int R) {
if (L == R) return a[L];
int level = __builtin_ctz(mask[L] ^ mask[R]);
return Secret(memo[level][L], memo[level][R]);
}
