二叉树的右视图

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 * 求二叉树的右视图
 * @param xianxu int整型一维数组 先序遍历
 * @param zhongxu int整型一维数组 中序遍历
 * @return int整型一维数组
 */
function solve( xianxu ,  zhongxu ) {
    // write code here
    function TreeNode(x){
        this.val = x
        this.left = null
        this.right = null
    }
    function build(xianxu,zhongxu){
        if(xianxu.length ==0 || zhongxu.length ==0) return null
        let root = new TreeNode(xianxu[0])
        let index = zhongxu.indexOf(xianxu[0])
        root.left = build(xianxu.slice(1,index+1),zhongxu.slice(0,index))
        root.right = build(xianxu.slice(index+1),zhongxu.slice(index+1))
        return root
    }
    let root = build(xianxu,zhongxu)
    let result = []
    let stack = [root]
    let temp = []
    let len = 0
    while(len = stack.length){
        for(let i=0;i<len;i++){
            let node = stack.shift()
            temp.push(node.val)
            if(node.left) stack.push(node.left)
            if(node.right) stack.push(node.right)
        }
        result.push(temp.pop())
        temp.length = 0
    }
    return result
}
module.exports = {
    solve : solve
};