以下代码在运行root=[1,2]示例中出错

Question

以下代码在运行root=[1,2]示例中出错，请问怎么修改，为什么会错：

代码为力扣110题

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
int height(struct TreeNode* root) {
    if (root == NULL) {
        return 0;
    } else {
        return fmax(height(root->left), height(root->right)) + 1;
    }
}

int minDepth(struct TreeNode* root) {
    if(root==NULL){
        return 0;
    }
    int hl=height(root->left);
    int hr=height(root->right);
    if(hl==0 && hr==0 && hr==hl){
        return 1;
    }else if(hl==0 || hl>=hr){
        return hr+1;
    }else{
        return hl+1;
    }
}