题解 | #求二叉树的层序遍历#

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

/**
 *
 * @param root TreeNode类
 * @return int整型二维数组
 */
// function levelOrder( root ) {
//     // write code here
//     let res = []
//     let arr = []
//     arr.push(root)

//         while(arr.length>0){
//             let res1 = []
//             let newArr = []
//             arr.forEach(v=>{
//                 res1.push(v.val)
//                 v.left&&newArr.push(v.left)
//                 v.right&&newArr.push(v.right)
//             })
//             arr = newArr
//             res.push(res1)

//         }
//     return res

// }
function levelOrder(root) {
    // write code here
    if(root===null) return []
    let res = [];
    let arr = [];
    arr.push(root);
    while (arr.length > 0) {
        let newArr = [];
        let row = [];
        arr.forEach((v) => {
            row.push(v.val);
            v.left && newArr.push(v.left);
            v.right && newArr.push(v.right);
        });
        arr = newArr;
        res.push(row);
    }
    return res;
}
module.exports = {
    levelOrder: levelOrder,
};