题解 | #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
    let res = []
    // if(pRoot.val === undefined && pRoot.left === undefined && pRoot.right === undefined){
    //     return res
    // }
    if(!pRoot){
        return res
    }
    let arr = []
    const stack1 = [];
    const stack2 = [];
    stack1.push (pRoot) ;
    while(stack1.length!=0 || stack2.length!=0){
        while(stack1.length!=0){
            arr.push(stack1[stack1.length-1].val);
            if(stack1[stack1.length-1].left)
                stack2.push(stack1[stack1.length-1].left)
            if(stack1[stack1.length-1].right)
                stack2.push(stack1[stack1.length-1].right)
            stack1.pop();
        }
        if(arr.length)
            res.push(arr)
        arr = []

        while(stack2.length!=0){
            arr.push(stack2[stack2.length-1].val);
            if(stack2[stack2.length-1].right)
                stack1.push(stack2[stack2.length-1].right)
            if(stack2[stack2.length-1].left)
                stack1.push(stack2[stack2.length-1].left)
            stack2.pop();
        }
        if(arr.length)
            res.push(arr)
        arr = []
    }
    return res
}
module.exports = {
    Print : Print
};