Day8-9

235. Lowest Common Ancestor of a Binary Search Tree/235. Lowest Common Ancestor of a Binary Search Tree.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_235._Lowest_Common_Ancestor_of_a_Binary_Search_Tree</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

235. Lowest Common Ancestor of a Binary Search Tree/Program.cs

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+namespace _235._Lowest_Common_Ancestor_of_a_Binary_Search_Tree;
+
+internal class Program
+{
+    static void Main(string[] args)
+    {
+        TreeNode root = new TreeNode(6);
+        root.left = new TreeNode(2) { left = new TreeNode(0), right = new TreeNode(4) { left = new TreeNode(3), right = new TreeNode(5) } };
+        root.right = new TreeNode(8) { left = new TreeNode(7), right = new TreeNode(9) };
+        Console.WriteLine(new Solution().LowestCommonAncestor(root, new TreeNode(3), new TreeNode(5)).val);
+    }
+}

235. Lowest Common Ancestor of a Binary Search Tree/Solution.cs

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+namespace _235._Lowest_Common_Ancestor_of_a_Binary_Search_Tree;
+
+public class Solution
+{
+    public TreeNode? LowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q)
+    {
+        int min = Math.Min(p.val, q.val);
+        int max = Math.Max(p.val, q.val);
+        while(true)
+        {
+            if (root == null)
+                return null;
+            else if (min <= root.val && max>=root.val)
+                return root;
+            else if (root.val >= p.val)
+                root = root.left!;
+            else
+                root = root.right!;
+        }
+    }
+}

235. Lowest Common Ancestor of a Binary Search Tree/TreeNode.cs

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+namespace _235._Lowest_Common_Ancestor_of_a_Binary_Search_Tree;
+
+//Definition for a binary tree node.
+public class TreeNode {
+    public int val;
+    public TreeNode? left;
+    public TreeNode? right;
+    public TreeNode(int x) { val = x; }
+}