algorithm001
diff --git a/Week_03/id_86/LeetCode_104_086.cs b/Week_03/id_86/LeetCode_104_086.cs
@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AlgorithmTest
+{
+    class LeetCode_104_086
+    {
+        public int MaxDepth(TreeNode root)
+        {
+            if (root == null) return 0;
+            return Math.Max(MaxDepth(root.left), MaxDepth(root.right)) + 1;
+        }
+    }
+}
diff --git a/Week_03/id_86/LeetCode_429_086.cs b/Week_03/id_86/LeetCode_429_086.cs
@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AlgorithmTest
+{
+    class LeetCode_429_086
+    {
+        public IList<IList<int>> LevelOrder(Node root)
+        {
+            IList<IList<int>> result = new List<IList<int>>();
+
+            if (root != null)
+            {
+                var q = new Queue<Node>();
+                q.Enqueue(root);
+
+                while (q.Count != 0)
+                {
+                    int num = q.Count;
+                    IList<int> r = new List<int>();
+
+                    for (int i = 0; i < num; i++)
+                    {
+                        Node n = q.Dequeue();
+                        r.Add(n.val);
+                        foreach (Node c in n.children)
+                        {
+                            q.Enqueue(c);
+                        }
+                    }
+                    result.Add(r);
+                }
+            }
+            return result;
+        }
+    }
+}
+
+
diff --git a/Week_04/id_86/LeetCode_169_086.cs b/Week_04/id_86/LeetCode_169_086.cs
@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AlgorithmTest
+{
+    class LeetCode_169_086
+    {
+        public int MethodFor169_1(int[] num)
+        {
+            int n = num[0];
+            int count = 1;
+
+            for (int i = 1; i < num.Length; i++)
+            {
+                if (count == 0)
+                {
+                    count++;
+                    n = num[i];
+                }
+                else if (n == num[i])
+                {
+                    count++;
+                }
+                else count--;
+
+            }
+            return n;
+        }
+
+        //直接调用 Array.Sort
+        public int MethodFor169_2(int[] num)
+        {
+            Array.Sort(num);
+            return num[num.Length / 2];
+        }
+    }
+}
diff --git a/Week_04/id_86/LeetCode_746_086.cs b/Week_04/id_86/LeetCode_746_086.cs
@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace AlgorithmTest
+{
+    class LeetCode_746_086
+    {
+        public int MethodFor746_1(int[] cost)
+        {
+            for (int i = 2; i < cost.Length; i++)
+            {
+                cost[i] += Math.Min(cost[i - 2], cost[i - 1]);
+            }
+
+            return Math.Min(cost[cost.Length - 1], cost[cost.Length - 2]);
+        }
+    }
+}