题目：

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代码(首刷看解析 2024年1月30日）：

class Solution {
public:int depth(TreeNode* root) {if (root == nullptr) return 0;int leftHeight = depth(root->left);if (leftHeight == -1) return -1;int rightHeight = depth(root->right);if (rightHeight == -1) return -1;if (abs(leftHeight - rightHeight) > 1) {return -1;} else {return 1 + max(leftHeight,rightHeight);}}bool isBalanced(TreeNode* root) {if (root == nullptr) return true;return depth(root) == -1 ? false : true;}
};