给出后序中序还原二叉树

/*
给出后序中序还原二叉树，并写出前序遍历

后序遍历： FGCDEBA

中序遍历： FCGADBE

/

/*
A
C B
F G D E


前序遍历： ACFGBDE
/

var hou = [‘f’, ‘g’, ‘c’, ‘d’, ‘e’, ‘b’, ‘a’];
var zhong = [‘f’, ‘c’, ‘g’, ‘a’, ‘d’, ‘b’, ‘e’];

function Node(value) {
this.value = value;
this.left = null;
this.right = null;
}

function f1(zhong, hou) {
if (hou == null || zhong == null || hou.length == 0 || zhong.length == 0 || hou.length != zhong.length) return null;

var root = new Node(hou[hou.length - 1]);<br />    var index = zhong.indexOf(root.value); // 找到根节点在中序遍历中的位置<br />    var houLeft = hou.slice(0, index); //后序遍历的左子树<br />    var houRight = hou.slice(index, hou.length - 1); //后序遍历的右子树
var zhongLeft = zhong.slice(0, index);//中序遍历的左子树<br />    var zhongRight = zhong.slice(index + 1, zhong.length);//中序遍历的右子树<br />    root.left = f1(zhongLeft, houLeft);//根据左子树的后序和中序还原左子树并赋值给root.left<br />    root.right = f1(zhongRight,houRight);//根据右子树的后序和中序还原右子树并赋值给root.right<br />    return root;<br />}

var root = f1(zhong, hou);

console.log(root.left);
console.log(root.right);