110. Balanced Binary Tree

解題思路

由上往下一個個 node 去檢查

程式碼

class Solution {
public:
    int getDepth(TreeNode* p)
    {
        if(p == nullptr)
            return 0;
        return max(getDepth(p->left), getDepth(p->right)) + 1;
    }
    bool isBalanced(TreeNode* root) {
        if(root == nullptr)
            return true;

        int left = getDepth(root->left);
        int right = getDepth(root->right);
        if (abs(left - right) > 1)
            return false;
        return isBalanced(root->left) && isBalanced(root->right);
    }
};