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 {
private:
    int getDepth(TreeNode* root){
        if(root == nullptr) return 0;
        int leftHeight = getDepth(root->left);
        if(leftHeight == -1) return -1;
        int rightHeight = getDepth(root -> right);
        if(rightHeight == -1) return -1;
        if(abs(leftHeight - rightHeight) > 1) return -1;
        return(max(leftHeight,rightHeight) + 1);

    }
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
        return getDepth(pRoot) != -1;
    }
};