题解 | 判断是不是平衡二叉树
判断是不是平衡二叉树
https://www.nowcoder.com/practice/8b3b95850edb4115918ecebdf1b4d222
1、判断左右子树高
2、判断左右子树是否是平衡二叉树
/** * 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 */ int treeHigh(TreeNode* pRoot) { if(pRoot == nullptr) return 0; return max(treeHigh(pRoot->left), treeHigh(pRoot->right))+1; } bool IsBalanced_Solution(TreeNode* pRoot) { if(pRoot == nullptr) return true; int left = treeHigh(pRoot->left); int right = treeHigh(pRoot->right); if(left - right > 1|| left - right < -1) return false; // 递归判断左右子树 return IsBalanced_Solution(pRoot->left) && IsBalanced_Solution(pRoot->right); } };