Day10

617. Merge Two Binary Trees/617. Merge Two Binary Trees.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_617._Merge_Two_Binary_Trees</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

617. Merge Two Binary Trees/Program.cs

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+namespace _617._Merge_Two_Binary_Trees;
+
+internal class Program
+{
+    static void Main(string[] args)
+    {
+        TreeNode root1 = new TreeNode(1);
+        root1.left = new TreeNode(3) { left = new TreeNode(5) };
+        root1.right = new TreeNode(2);
+
+
+        TreeNode root2 = new TreeNode(2);
+        root2.left = new TreeNode(1) { right = new TreeNode(4) };
+        root2.right = new TreeNode(3) { right = new TreeNode(7) };
+        var res = new Write().LevelOrder(new Solution().MergeTrees(root1, root2)!);
+        Console.WriteLine($"\nOutput");
+        foreach (var row in res)
+            Console.WriteLine(String.Join(" ", row));
+    }
+
+    public class Write
+    {
+        public IList<IList<int>> LevelOrder(TreeNode root)
+        {
+            List<IList<int>> output = new List<IList<int>>();
+            RecursiveTraversal(output, new List<TreeNode>() { root });
+            return output;
+        }
+
+        private void RecursiveTraversal(List<IList<int>> output, List<TreeNode> curLevel)
+        {
+            if (curLevel.Count == 0)
+                return;
+            List<int> levelValues = new List<int>();
+            foreach (var n in curLevel)
+            {
+                if (n == null)
+                    continue;
+                levelValues.Add(n.val);
+            }
+            if (levelValues.Count == 0)
+                return;
+            output.Add(levelValues);
+
+            List<TreeNode> nextLevel = new List<TreeNode>();
+            foreach (var n in curLevel)
+            {
+                if (n == null)
+                    continue;
+                if (n.left != null)
+                    nextLevel.Add(n.left);
+                if (n.right != null)
+                    nextLevel.Add(n.right);
+            }
+            RecursiveTraversal(output, nextLevel);
+        }
+    }
+}

617. Merge Two Binary Trees/Solution.cs

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+namespace _617._Merge_Two_Binary_Trees;
+
+public class Solution
+{
+    public TreeNode? MergeTrees(TreeNode root1, TreeNode root2)
+    {
+        if (root1 == null && root2 == null)
+            return null;
+        else if (root1 == null)
+            return root2;
+        else if (root2 == null)
+            return root1;
+        var res = new TreeNode();
+        RecursionMerge(res, root1, root2);
+        return res;
+    }
+
+    private void RecursionMerge(TreeNode cur, TreeNode? t1, TreeNode? t2)
+    {
+        if (t1 != null)
+            cur.val += t1.val;
+        if (t2 != null)
+            cur.val += t2.val;
+        cur.left = (t1?.left != null || t2?.left != null) ? new TreeNode() : null;
+        cur.right = (t1?.right != null || t2?.right != null) ? new TreeNode() : null;
+        if (cur.left != null)
+            RecursionMerge(cur.left, t1?.left, t2?.left);
+        if (cur.right != null)
+            RecursionMerge(cur.right, t1?.right, t2?.right);
+    }
+}

617. Merge Two Binary Trees/TreeNode.cs

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+namespace _617._Merge_Two_Binary_Trees;
+
+
+//Definition for a binary tree node.
+public class TreeNode
+{
+    public int val;
+    public TreeNode? left;
+    public TreeNode? right;
+    public TreeNode(int val = 0, TreeNode? left = null, TreeNode? right = null)
+    {
+        this.val = val;
+        this.left = left;
+        this.right = right;
+    }
+}