Swift-创建二叉查找树

题目:给定一个有序整数数组，元素各不相同且按照升序排列，编写一个算法，创建一个高度最小的二叉查找树.二叉查找树是指对于任意一个结点，左边的结点均小于它，右边的结点均大于它.

核心代码:
<pre><code>` func createMinBST(arr:[Int],start:Int,end:Int) -> TreeNode? {

    if arr.count == 0 {
        return nil
    }
    
    if start < 0 || end < 0 {
        return nil
    }
    
    if start > end {
        return nil
    }
    
    let mid:Int = (start + end) / 2
    
    let treeNode:TreeNode = TreeNode()
    treeNode.data = "\(arr[mid])"
    treeNode.leftChild = createMinBST(arr: arr, start: start, end: mid - 1)
    treeNode.rightChild = createMinBST(arr: arr, start: mid + 1, end: end)
    
    return treeNode
}`</code></pre>

测试代码:
<pre><code>var binarySearchTree:BinarySearchTree = BinarySearchTree() var searchData:[Int] = [1,2,3,4,5,6,7] var searchNode:TreeNode? = binarySearchTree.createMinBST(arr: searchData, start: 0, end: searchData.count - 1) tree.treeLevelOrder(root: searchNode) print("FlyElephant")</code></pre>

FlyElephant.png