Day4

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;
+    }
+}