1.描述

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

2.分析

3.代码

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
 
struct TreeNode* BST(int* nums, int from, int to) {
    if (from > to) return NULL;
    int mid = (from + to) / 2;
    struct TreeNode* node = (struct TreeNode*)malloc(sizeof(struct TreeNode));
    node->val = nums[mid];
    node->left = BST(nums, from, mid - 1);
    node->right = BST(nums, mid + 1, to);
    return node;
}

struct TreeNode* sortedArrayToBST(int* nums, int numsSize) {
    if (NULL == nums || 0 >= numsSize) return NULL;
    return BST(nums, 0, numsSize - 1);
}