题解 | #判断是不是平衡二叉树#

/**
 * struct TreeNode {
 *  int val;
 *  struct TreeNode *left;
 *  struct TreeNode *right;
 *  TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
  public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param pRoot TreeNode类
     * @return bool布尔型
     */
    bool IsBalanced_Solution(TreeNode* pRoot) {
        // write code here
        if (pRoot == nullptr) {
            return true;
        }
        return abs(height(pRoot->left) - height(pRoot->right)) <= 1 &&
               IsBalanced_Solution(pRoot->left) && IsBalanced_Solution(pRoot->right);
    }

    int height(TreeNode* pRoot) {
        if (pRoot == nullptr) {
            return 0;
        }
        return height(pRoot->left) > height(pRoot->right) ? height(
                   pRoot->left) + 1 : height(pRoot->right) + 1;
    }
};