2023年6月22日发(作者：)

2021-09-14华为OD⾯试题华为OD⾯试题⼿撕代码：⼆叉树分为⼴度遍历和深度遍历，在技术⼀⾯时遇到⼀个⼴度遍历的问题，题⽬如下：给定义⼀个⼆叉树，树的结构如下：需要遍历每⼀层节点的值，并输出如下结果：[ [5],[3, 7],[2, 4, 6, 8],[10, 11]]以前做的最多的都是深度遍历法，⼴度遍历有点懵懵的，后来想了下，就这样做了，什么也不说了直接上代码：1. 节点定义//节点的定义 public static class TreeNode { private int value; private TreeNode left = null; private TreeNode right = null; public TreeNode(int value, TreeNode left, TreeNode right) { = value; = left; = right; } public TreeNode(int value){ = value; } public void setLeftNode(TreeNode node) { = node; } public void setRightNode(TreeNode node){ = node; } public TreeNode getLeftNode(){ return ; } public TreeNode getRightNode(){ return ; } public int getData(){ return ; } }2. 创建树public static TreeNode createTree() { TreeNode firstLeft = new TreeNode(3); TreeNode firstRighe = new TreeNode(7); TreeNode root = new TreeNode(5, firstLeft, firstRighe); TreeNode leftSecondL = new TreeNode(2); TreeNode rightSecondL = new TreeNode(4); TreeNode leftSecondR = new TreeNode(6); TreeNode rightSecondR = new TreeNode(8); tNode(leftSecondL); htNode(rightSecondL); tNode(leftSecondR); htNode(rightSecondR); TreeNode leftThirdL = new TreeNode(10); TreeNode rightThirdL = new TreeNode(11); tNode(leftThirdL); htNode(rightThirdL); return root; }3、返回层级listpublic static List> treeList = new ArrayList<>();public static void wideSerch(TreeNode root){ List list=new ArrayList(); //链表⽤来存储每⼀层数据 Queue queue=new LinkedList();//当前层队列 Queue queue2=new LinkedList();//下⼀层队列 if(root==null){ return; } (root);//先把根节点⼊队，使队列不为空，进⼊循环 while(!y()) { TreeNode node = (); (a()); if (tNode() != null) (tNode()); if (htNode() != null) (htNode()); if (y()) { (list); list=new ArrayList(); //链表⽤来存储每⼀层数据 (queue2); (); } } }4、主函数输出listpublic static void main(String[] args) { TreeNode root=Tree();//调⽤了⾃⼰写的静态⽅法创建⼀棵树 wideSerch(root); for(List one:treeList){ n(one); }}总结：就是这么简单，⼀层⼀层的遍历。