Day4

118. Pascal's Triangle/118. Pascal's Triangle.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_118._Pascal_s_Triangle</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

118. Pascal's Triangle/Program.cs

@@ -0,0 +1,12 @@
+namespace _118._Pascal_s_Triangle
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var res = new Solution().Generate(300);
+            foreach(var r in res)
+                Console.WriteLine(String.Join(" ", r));
+        }
+    }
+}

118. Pascal's Triangle/Solution.cs

@@ -0,0 +1,26 @@
+namespace _118._Pascal_s_Triangle;
+
+public class Solution
+{
+    public IList<IList<int>> Generate(int numRows)
+    {
+        List<IList<int>> triangle = new List<IList<int>>() { new List<int> { 1 } };
+        if(numRows > 1)
+            triangle.Add(new List<int>() { 1,1 });
+        numRows -= 2;
+        while (numRows-- > 0)
+        {
+            IList<int> prev = triangle[^1];
+            int nextCount = prev.Count;
+            List<int> row = new List<int>() { 1 };
+            for(int i = 1; i < nextCount; i++)
+            {
+                row.Add(prev[i-1] + prev[i]);
+            }
+            row.Add(1); 
+            triangle.Add(row);
+        }
+
+        return triangle;
+    }
+}

142. Linked List Cycle II/142. Linked List Cycle II.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_142._Linked_List_Cycle_II</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

142. Linked List Cycle II/ListNode.cs

@@ -0,0 +1,37 @@
+namespace _142._Linked_List_Cycle_II;
+
+//Definition for singly-linked list.
+public class ListNode
+{
+    public int val;
+    public ListNode? next;
+    public ListNode(int val = 0, ListNode? next = null)
+    {
+        this.val = val;
+        this.next = next;
+    }
+
+    public static ListNode Create(int[] nums)
+    {
+        ListNode l = new ListNode(nums[0]);
+        ListNode cur = l;
+        for (int i = 1; i < nums.Length; i++)
+        {
+            cur.next = new ListNode(nums[i]);
+            cur = cur.next;
+        }
+        return l;
+    }
+
+    public override string ToString()
+    {
+        List<int> list = new List<int>();
+        ListNode? cur = this;
+        while (cur != null)
+        {
+            list.Add(cur.val);
+            cur = cur.next;
+        }
+        return String.Join(" ", list);
+    }
+}

142. Linked List Cycle II/Program.cs

@@ -0,0 +1,15 @@
+namespace _142._Linked_List_Cycle_II
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var l1 = new ListNode(3);
+            var l2 = new ListNode(2);
+
+            l1.next = l2;
+            l2.next = l1;
+            Console.WriteLine(new Solution().DetectCycle(l1)?.val);
+        }
+    }
+}

142. Linked List Cycle II/Solution.cs

@@ -0,0 +1,28 @@
+namespace _142._Linked_List_Cycle_II;
+
+public class Solution
+{
+    public ListNode? DetectCycle(ListNode head)
+    {
+        ListNode? cur = head;
+        int bit = 1 << 28;
+        int curAbs = 0;
+        while (cur!=null && (curAbs & bit) == 0)
+        {
+            cur.val ^= bit;
+            cur = cur.next;
+            if(cur != null)
+                curAbs = cur.val < 0 ? (cur.val * -1) : cur.val;
+        }
+        cur = head;
+        curAbs = cur.val < 0 ? (cur.val * -1) : cur.val;
+        while (cur != null && (curAbs & bit) != 0)
+        {
+            cur.val ^= bit;
+            cur = cur.next;
+            if (cur != null)
+                curAbs = cur.val < 0 ? (cur.val * -1) : cur.val;
+        }
+        return cur;
+    }
+}

189. Rotate Array/189. Rotate Array.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_189._Rotate_Array</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

189. Rotate Array/Program.cs

@@ -0,0 +1,12 @@
+namespace _189._Rotate_Array
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var arr = new int[] { 1, 2, 3, 4, 5, 6};
+            new Solution().Rotate(arr, 3);
+            Console.WriteLine(String.Join(" ", arr));
+        }
+    }
+}

189. Rotate Array/Solution.cs

@@ -0,0 +1,34 @@
+namespace _189._Rotate_Array;
+
+public class Solution
+{
+    public void Rotate(int[] nums, int k)
+    {
+        k %= nums.Length;
+        if (k == 0)
+            return;
+        int oneCycleLen = nums.Length/ GCD(nums.Length, k);
+        for (int i = 0; i < nums.Length / oneCycleLen; i++)
+            MoveTo(nums, nums[i], i + k, k, oneCycleLen);
+    }
+
+    private static void MoveTo(int[] array, int value, int to, int step, int curLen)
+    {
+        while (curLen-- > 0)
+        {
+            if (to >= array.Length)
+                to -= array.Length;
+            int buf = array[to];
+            array[to] = value;
+            to += step;
+            value = buf;
+        }
+    }
+
+    private static int GCD(int a, int b)
+    {
+        return b == 0 ? a : GCD(b, a % b);
+    }
+
+    
+}

566. Reshape the Matrix/566. Reshape the Matrix.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_566._Reshape_the_Matrix</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

566. Reshape the Matrix/Program.cs

@@ -0,0 +1,12 @@
+namespace _566._Reshape_the_Matrix
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var res = new Solution().MatrixReshape(new int[][] { new int[] { 1,2 }, new int[] { 4, 5 } }, 2, 4);
+            foreach(var row in res)
+                Console.WriteLine(String.Join(" ", row));
+        }
+    }
+}

566. Reshape the Matrix/Solution.cs

@@ -0,0 +1,27 @@
+namespace _566._Reshape_the_Matrix;
+
+public class Solution
+{
+    public int[][] MatrixReshape(int[][] mat, int r, int c)
+    {
+        int[][] result = new int[r][];
+        for (int i = 0; i < result.Length; i++)
+            result[i] = new int[c];
+
+        int height = mat.Length;
+        int width = mat[0].Length;
+        int size = r * c;
+        if (size != height * width)
+            return mat;
+        for(int i = 0; i < size; i++)
+        {
+            int ySource = i / width;
+            int xSource = i % width;
+
+            int yTo = i / c;
+            int xTo = i % c;
+            result[yTo][xTo] = mat[ySource][xSource];
+        }
+        return result;
+    }
+}

876. Middle of the Linked List/876. Middle of the Linked List.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_876._Middle_of_the_Linked_List</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

876. Middle of the Linked List/ListNode.cs

@@ -0,0 +1,37 @@
+namespace _876._Middle_of_the_Linked_List;
+
+//Definition for singly-linked list.
+public class ListNode
+{
+    public int val;
+    public ListNode? next;
+    public ListNode(int val = 0, ListNode? next = null)
+    {
+        this.val = val;
+        this.next = next;
+    }
+
+    public static ListNode Create(int[] nums)
+    {
+        ListNode l = new ListNode(nums[0]);
+        ListNode cur = l;
+        for (int i = 1; i < nums.Length; i++)
+        {
+            cur.next = new ListNode(nums[i]);
+            cur = cur.next;
+        }
+        return l;
+    }
+
+    public override string ToString()
+    {
+        List<int> list = new List<int>();
+        ListNode? cur = this;
+        while (cur != null)
+        {
+            list.Add(cur.val);
+            cur = cur.next;
+        }
+        return String.Join(" ", list);
+    }
+}

876. Middle of the Linked List/Program.cs

@@ -0,0 +1,13 @@
+namespace _876._Middle_of_the_Linked_List
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var l1 = ListNode.Create(new int[] { 1,2,3,4,5});
+            var l2 = ListNode.Create(new int[] { 1,2,3,4,5,6});
+            Console.WriteLine(new Solution().MiddleNode(l1).val);
+            Console.WriteLine(new Solution().MiddleNode(l2).val);
+        }
+    }
+}

876. Middle of the Linked List/Solution.cs

@@ -0,0 +1,15 @@
+namespace _876._Middle_of_the_Linked_List;
+
+public class Solution
+{
+    public ListNode MiddleNode(ListNode? head)
+    {
+        ListNode result = head!;
+        while(head?.next != null)
+        {
+            head = head?.next?.next;
+            result = result!.next!;
+        }
+        return result;
+    }
+}

977. Squares of a Sorted Array/977. Squares of a Sorted Array.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_977._Squares_of_a_Sorted_Array</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

977. Squares of a Sorted Array/Program.cs

@@ -0,0 +1,11 @@
+namespace _977._Squares_of_a_Sorted_Array
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var res = new Solution().SortedSquares(new int[] { -7, -2,-1 });
+            Console.WriteLine(String.Join(" ", res));
+        }
+    }
+}

977. Squares of a Sorted Array/Solution.cs

@@ -0,0 +1,49 @@
+namespace _977._Squares_of_a_Sorted_Array;
+
+public class Solution
+{
+    public int[] SortedSquares(int[] nums)
+    {
+        int[] res = new int[nums.Length];
+        int firstNonNegative = -1;
+        for(int i = 0; i < nums.Length; i++)
+        {
+            if (nums[i] >= 0)
+            {
+                firstNonNegative = i;
+                break;
+            }
+        }
+
+        int resIndex = 0;
+        int positiveIndex = firstNonNegative;
+        int negativeIndex = firstNonNegative!=-1 ? positiveIndex - 1 : nums.Length-1;
+        while(resIndex < nums.Length)
+        {
+            if(negativeIndex>=0 && positiveIndex < nums.Length && positiveIndex>=0)
+            {
+                if (nums[negativeIndex]*-1 < nums[positiveIndex])
+                {
+                    res[resIndex++] = nums[negativeIndex] * nums[negativeIndex];
+                    negativeIndex--;
+                }
+                else
+                {
+                    res[resIndex++] = nums[positiveIndex] * nums[positiveIndex];
+                    positiveIndex++;
+                }
+            }
+            else if(negativeIndex >= 0)
+            {
+                res[resIndex++] = nums[negativeIndex]* nums[negativeIndex];
+                negativeIndex--;
+            }
+            else if(positiveIndex >= 0)
+            {
+                res[resIndex++] = nums[positiveIndex] * nums[positiveIndex];
+                positiveIndex++;
+            }
+        }
+        return res;
+    }
+}

Leetcode.sln

@@ -25,13 +25,25 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "121. Best Time to Buy and S
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "21. Merge Two Sorted Lists", "21. Merge Two Sorted Lists\21. Merge Two Sorted Lists.csproj", "{3063143F-AAF9-4B23-8D98-A7236E01AA27}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "206. Reverse Linked List", "206. Reverse Linked List\206. Reverse Linked List.csproj", "{1C1BEA62-325F-48F8-8CC0-D5828A62F14F}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "206. Reverse Linked List", "206. Reverse Linked List\206. Reverse Linked List.csproj", "{1C1BEA62-325F-48F8-8CC0-D5828A62F14F}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "704. Binary Search", "704. Binary Search\704. Binary Search.csproj", "{69081812-D523-4211-AE09-9DAF8E9B83D8}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "704. Binary Search", "704. Binary Search\704. Binary Search.csproj", "{69081812-D523-4211-AE09-9DAF8E9B83D8}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "278. First Bad Version", "278. First Bad Version\278. First Bad Version.csproj", "{3BA31E13-3748-4C4A-BE68-24D2E3DF0DC1}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "278. First Bad Version", "278. First Bad Version\278. First Bad Version.csproj", "{3BA31E13-3748-4C4A-BE68-24D2E3DF0DC1}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "35. Search Insert Position", "35. Search Insert Position\35. Search Insert Position.csproj", "{B595BB51-666D-4E39-86EE-F9A3B8D8DA58}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "35. Search Insert Position", "35. Search Insert Position\35. Search Insert Position.csproj", "{B595BB51-666D-4E39-86EE-F9A3B8D8DA58}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "876. Middle of the Linked List", "876. Middle of the Linked List\876. Middle of the Linked List.csproj", "{2510B3B5-87EE-44AB-A2A7-BCAE9E6E91C6}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "566. Reshape the Matrix", "566. Reshape the Matrix\566. Reshape the Matrix.csproj", "{DD4A53CF-D840-48BF-8F8F-33E39D492BD3}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "118. Pascal's Triangle", "118. Pascal's Triangle\118. Pascal's Triangle.csproj", "{E1BB66AE-E4E6-441F-9B5C-1B7FFDF7912C}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "977. Squares of a Sorted Array", "977. Squares of a Sorted Array\977. Squares of a Sorted Array.csproj", "{F0B9DD20-6230-4381-8814-072C2E159624}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "189. Rotate Array", "189. Rotate Array\189. Rotate Array.csproj", "{CAF5FFD6-9598-412D-8569-EB62136D34C8}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "142. Linked List Cycle II", "142. Linked List Cycle II\142. Linked List Cycle II.csproj", "{EBA96217-EAD0-456C-B1C6-79A7A227ED0A}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -99,6 +111,30 @@ Global
 		{B595BB51-666D-4E39-86EE-F9A3B8D8DA58}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{B595BB51-666D-4E39-86EE-F9A3B8D8DA58}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{B595BB51-666D-4E39-86EE-F9A3B8D8DA58}.Release|Any CPU.Build.0 = Release|Any CPU
+		{2510B3B5-87EE-44AB-A2A7-BCAE9E6E91C6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2510B3B5-87EE-44AB-A2A7-BCAE9E6E91C6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2510B3B5-87EE-44AB-A2A7-BCAE9E6E91C6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2510B3B5-87EE-44AB-A2A7-BCAE9E6E91C6}.Release|Any CPU.Build.0 = Release|Any CPU
+		{DD4A53CF-D840-48BF-8F8F-33E39D492BD3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DD4A53CF-D840-48BF-8F8F-33E39D492BD3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DD4A53CF-D840-48BF-8F8F-33E39D492BD3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DD4A53CF-D840-48BF-8F8F-33E39D492BD3}.Release|Any CPU.Build.0 = Release|Any CPU
+		{E1BB66AE-E4E6-441F-9B5C-1B7FFDF7912C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E1BB66AE-E4E6-441F-9B5C-1B7FFDF7912C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E1BB66AE-E4E6-441F-9B5C-1B7FFDF7912C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E1BB66AE-E4E6-441F-9B5C-1B7FFDF7912C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F0B9DD20-6230-4381-8814-072C2E159624}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F0B9DD20-6230-4381-8814-072C2E159624}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F0B9DD20-6230-4381-8814-072C2E159624}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F0B9DD20-6230-4381-8814-072C2E159624}.Release|Any CPU.Build.0 = Release|Any CPU
+		{CAF5FFD6-9598-412D-8569-EB62136D34C8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{CAF5FFD6-9598-412D-8569-EB62136D34C8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{CAF5FFD6-9598-412D-8569-EB62136D34C8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{CAF5FFD6-9598-412D-8569-EB62136D34C8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{EBA96217-EAD0-456C-B1C6-79A7A227ED0A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{EBA96217-EAD0-456C-B1C6-79A7A227ED0A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{EBA96217-EAD0-456C-B1C6-79A7A227ED0A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{EBA96217-EAD0-456C-B1C6-79A7A227ED0A}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE