Method get_val

Data Structures/Persistent Queue.cpp:29–31

get the ith value of the rth array

  }
  // get the ith value of the rth array
  T get_val(int r, int i) {
    return get_val(root[r], i, 0, n - 1);
  }
  T get_val(node* cur, int i, int l, int r) {
    if (l == r) return cur -> x;
    if (i <= ((l + r) >> 1)) return get_val(cur -> l, i, l, (l + r) >> 1);