Level traversal tree.cs

Author: jackzhenguo

Diff for: Tree/Tree.TreeLib/LevelTraversalTree.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Tree.TreeLib
+{
+    public class LevelTraversalTree
+    {
+        public IList<IList<int>> LevelOrder(TreeNode root)
+        {
+            if (root == null)
+                return new List<IList<int>>();
+            IList<IList<int>> rtn = new List<IList<int>> { new List<int> { root.val } };
+            var tmp = getNextLevel(new List<TreeNode> { root });
+            if (tmp != null && tmp.Count > 0)
+            {
+                foreach (var item in tmp)
+                    rtn.Add(item);
+            }
+            return rtn;
+        }
+        private IList<IList<int>> getNextLevel(IList<TreeNode> curLevel)
+        {
+            if (curLevel == null || curLevel.Count == 0)
+                return null;
+            IList<IList<int>> rtn = new List<IList<int>>();
+            List<TreeNode> nextn = new List<TreeNode>();
+            foreach (var item in curLevel)
+            {
+                if (item.left != null)
+                    nextn.Add(item.left);
+                if (item.right != null)
+                    nextn.Add(item.right);
+            }
+            if (nextn.Count == 0)
+                return null;
+            rtn.Add(nextn.Select(r => r.val).ToList());
+            var children = getNextLevel(nextn);
+            if (children != null && children.Count > 0)
+            {
+                foreach (var item in children)
+                    rtn.Add(item);
+            }
+            return rtn;
+        }      
+    }
+}

Diff for: Tree/Tree.TreeLib/TravesalUsingStack.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Tree.TreeLib
+{
+    //二叉树的遍历，迭代版
+    public class TravesalUsingStack
+    {
+        public void PreOrder(TreeNode root)
+        {
+            if (root == null)
+                return;
+            Stack<TreeNode> s = new Stack<TreeNode>();
+            s.Push(root);
+            Console.WriteLine(root.val);
+            while(s.Count>0)
+            {
+                TreeNode node = (s.Peek as TreeNode).left;
+
+
+            }
+        }
+
+    }
+}