摘要：
Two methods:1. Traverse2. Divide & Conquer 1 // Traverse: usually do not have return value 2 public class Solution { 3 public void traverse(TreeNo... 阅读全文
摘要：
Use one queue + size variable 1 public class Solution { 2 public ArrayList> levelOrder(TreeNode root) { 3 ArrayList result = new ArrayList... 阅读全文