题解 | #判断是不是平衡二叉树#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 *
 * C语言声明定义全局变量请加上static，防止重复定义
 */

/**
 * 
 * @param pRoot TreeNode类 
 * @return bool布尔型
 */

int TreeDepth(struct TreeNode *p)
{
  if (!p)
    return 0;
  int LD, RD;
  LD = TreeDepth(p->left);
  RD = TreeDepth(p->right);
  return (LD > RD ? LD : RD) + 1;
}
//递归 满足平衡二叉树 且左右子树都是平衡二叉树
bool IsBalanced_Solution(struct TreeNode *pRoot)
{
  if (!pRoot)
    return true;
  int left = TreeDepth(pRoot->left);
  int right = TreeDepth(pRoot->right);
  if (abs(left - right) > 1)
    return false;

  return IsBalanced_Solution(pRoot->left) && IsBalanced_Solution(pRoot->right);
}