console.log(root)
    let nums1=[]
    let nums2=[]
    let nums3=[]
    function qianxu(root){
        if(!root) return
        nums1.push(root.val)
        if(root.left) {
            qianxu(root.left)
        }
        if(root.right) {
            qianxu(root.right)
        }
    }
    function zhongxu(root){
        if(!root) return
        if(root.left) {
            zhongxu(root.left)
        }
        nums2.push(root.val)
        if(root.right) {
            zhongxu(root.right)
        }
    }
    function houxu(root){
        if(!root) return
        if(root.left) {
            houxu(root.left)
        }
        if(root.right) {
            houxu(root.right)
        }
        nums3.push(root.val)
    }
    qianxu(root)
    zhongxu(root)
    houxu(root)
    let ret = []
    ret.push(nums1,nums2,nums3)
    return ret
}
module.exports = {
    threeOrders : threeOrders
};