108. Convert Sorted Array to Binary Search Tree - C

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */

// Node 생성
struct TreeNode* newNode(int val){
    struct TreeNode* new = malloc(sizeof(struct TreeNode));
    new->val = val;
    new->left = NULL;
    new->right = NULL;
    return new;
}

// BST 만들기
struct TreeNode* ArrayToBST(int* nums, int start, int end){
    if(start>end)
        return NULL;
    
    // sorted array가 주어지므로
    int mid = (start+end)/2;
    struct TreeNode* root = newNode(nums[mid]);
    
    root->left = ArrayToBST(nums,start,mid-1);
    
    root->right = ArrayToBST(nums,mid+1,end);
    
    return root;
}

struct TreeNode* sortedArrayToBST(int* nums, int numsSize){
    // 배열 크기 생각 (0 ~ numsSize-1)
    return ArrayToBST(nums, 0, numsSize-1);
}

Point

    // !!!!! sorted array가 주어지므로 !!!!!
    int mid = (start+end)/2;
    struct TreeNode* root = newNode(nums[mid]);
    
    root->left = ArrayToBST(nums,start,mid-1);
    
    root->right = ArrayToBST(nums,mid+1,end);

이진트리.. 다 까먹었다..