题解 | #JZ77 按之字形顺序打印二叉树#

```/* function TreeNode(x) {
    this.val = x;
    this.left = null;
    this.right = null;
} */
function Print(pRoot)
{
    // write code here
    if(pRoot === null ){return []}
    let resArr=[]
    let oddStack=[] //奇数层节点
    let evenStack=[] //偶数层节点
    let index=1
    oddStack.push(pRoot)  //第一层的根节点推入
    while(oddStack.length||evenStack.length){
        if(index%2===1){ //处理奇数层出栈，子节点入偶数层
            let temp=[]
            while(oddStack.length){
                let node=oddStack.pop()
                temp.push(node.val)
                if(node.left){evenStack.push(node.left)} //每一个奇数层子节点(如果存在)按顺序推入evenstack
                if(node.right){evenStack.push(node.right)}
            }
            
            resArr.push(temp)
            index++
            
        }
        else{ //处理偶数层出栈，子节点入奇数层
            let temp=[]
            while(evenStack.length){
                let node=evenStack.pop()
                temp.push(node.val)
                if(node.right){oddStack.push(node.right)} //每一个偶数层的子节点(如果存在)按顺序推入oddStack
                if(node.left){oddStack.push(node.left)}
            }
            
            resArr.push(temp)
            index++
           
        }
    }
    return resArr
}
module.exports = {
    Print : Print
};