Convert Sorted Array to Binary Search Tree

有序数组创建高度最小的二叉查找树

// class TreeNode{
//     constructor(val) {
//         this.val = val;
//         this.left = null;
//         this.right=null
//       }
// }
var sortedArrayToBST = function(nums) {
            function build(arr){
                if(arr.length===0){return null;}
                var mid=Math.floor(arr.length/2);
                var node=new TreeNode(arr[mid]);
                node.left=build(arr.slice(0,mid))
                node.right=build(arr.slice(mid+1,arr.length))
                return node
            }

            return build(nums);
};