height函数用于计算结点高度,当左右儿子高度差大于1,则停止计算返回-10。
时间复杂度:O(N)
C++代码:
class Solution {
public:
bool isBalanced(TreeNode* root) {
if (root == nullptr)
return true;
return height(root) + 10;
}
int height(TreeNode* r)
{
if (r == nullptr)
return -1;
int left = height(r->left);
int right = height(r->right);
if (left == -10 || right == -10)
return -10;
int diff = abs(left - right);
if (diff > 1)
return -10;
return max(right, left) + 1;
}
};