Convert Sorted Array to Binary Search Tree || LeetCode

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     struct TreeNode *left;
*     struct TreeNode *right;
* };
*/
struct TreeNode* built_bst(int* nums,int start,int end){
int mid;
mid=(start+end)/2;
if(start>end)return NULL;
struct TreeNode *p;
p=(struct TreeNode*)malloc(sizeof(struct TreeNode));
p->val=nums[mid];
p->left=built_bst(nums,start,mid-1);
p->right=built_bst(nums,mid+1,end );
return p;
}
struct TreeNode* sortedArrayToBST(int* nums, int numsSize) {
struct TreeNode *root;
root=built_bst(nums,0,numsSize-1);
return root;
}