Submission #714475

#	Time	Username	Problem	Language	Result	Execution time	Memory
714475		MattTheNub	Secret (JOI14_secret)	C++17	100 / 100	470 ms	4332 KiB

secret

#include "secret.h"

int *a;
int dat[18][1005]{0};
int mask[1005]{0};

void compute(int l, int r, int depth) {
  if (l == r)
    return;

  int mid = (l + r) / 2;
  dat[depth][mid] = a[mid];
  for (int i = mid - 1; i >= l; i--)
    dat[depth][i] = Secret(a[i], dat[depth][i + 1]);
  dat[depth][mid + 1] = a[mid + 1];
  for (int i = mid + 2; i <= r; i++)
    dat[depth][i] = Secret(dat[depth][i - 1], a[i]);
  for (int i = mid + 1; i <= r; i++) {
    mask[i] ^= 1 << depth;
  }
  compute(l, mid, depth + 1);
  compute(mid + 1, r, depth + 1);
}

void Init(int N, int A[]) {
  a = A;
  compute(0, N - 1, 0);
}

int Query(int L, int R) {
  if (L == R)
    return a[L];

  int x = __builtin_ctz(mask[L] ^ mask[R]);
  return Secret(dat[x][L], dat[x][R]);
}

• Subtask 1: 100 / 100