二叉树构建

const createTree = (arr) => { // 创建二叉树
    let tree = new Node(arr[0]);
    let Nodes = [tree];
    let i = 1;
    for (let node of Nodes){
        Nodes.push(node.left = new Node (arr[i]));
        i += 1;
        if (i == arr.length) return tree;
        Nodes.push(node.right = new Node(arr[i]));
        i += 1;
        if (i == arr.length) return tree;
    }
};