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
};