题解 | #从上往下打印二叉树#

/* function TreeNode(x) {
    this.val = x;
    this.left = null;
    this.right = null;
} */

function PrintFromTopToBottom(root)
{
    // write code here
    //使用bsf的思路即可
    let arr = [];
    let ret = [];
     if(!root) return [];
       arr = [root];
    while(arr.length){

        let head = arr.shift();
        ret.push(head.val)
         if(head.left) arr.push(head.left)
        if(head.right) arr.push(head.right)
    }
    return ret
}
module.exports = {
    PrintFromTopToBottom : PrintFromTopToBottom
};