题解 | #求二叉树的层序遍历#

package main
import . "nc_tools"
/*
 * type TreeNode struct {
 *   Val int
 *   Left *TreeNode
 *   Right *TreeNode
 * }
 */

/**
  * 
  * @param root TreeNode类 
  * @return int整型二维数组
*/
func levelOrder( root *TreeNode ) [][]int {
    res := make([][]int, 0)
    if root == nil {
        return res
    }
    s := make([]*TreeNode, 0 , 10)
    
    s = append(s, root)
    for {
        length := len(s)
        if length > 0 {
            curs := make([]int, 0)
            curNodes := make([]*TreeNode, 0)
            for i := 0; i < length ;i++ {
                cur := s[i]
                curs = append(curs, cur.Val)
                if cur.Left != nil {
                    curNodes = append(curNodes, cur.Left)    
                }
                 if cur.Right != nil {
                    curNodes = append(curNodes, cur.Right)    
                }
            } 
            s = curNodes
            res = append(res, curs)
        } else {
            break
        }
    }
    return res
}