挑战数据结构和算法面试题——二叉搜索树的后序遍历

bool judge_is_search_tree(int *a, int start, int end) {
  if (start == end) return true;
  if (start > end) return false;

  int root = a[end - 1];
  int i = start;
  while (i < end-1 && a[i] < root) i++;
  int pos = i;
  while (i < end-1) {
    if (a[i] < root) return false;
    i++;
  }

  bool left = judge_is_search_tree(a, 0, pos);
  bool right = judge_is_search_tree(a, pos, end-1);

  return left&&right;
}