Day i do not know

62. Unique Paths/62. Unique Paths.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_62._Unique_Paths</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

62. Unique Paths/Program.cs

@@ -0,0 +1,9 @@
+namespace _62._Unique_Paths;
+
+internal class Program
+{
+    static void Main(string[] args)
+    {
+        Console.WriteLine(new Solution().UniquePaths(10,10));
+    }
+}

62. Unique Paths/Solution.cs

@@ -0,0 +1,29 @@
+using System.Numerics;
+
+namespace _62._Unique_Paths;
+
+public class Solution
+{
+    public int UniquePaths(int min, int max)
+    {
+        min--;
+        max--;
+        if (min == 0 || max == 0)
+            return 1;
+        if(min > max)
+        {
+            min = min + max;
+            max = min - max;
+            min = min - max; 
+        }
+        return (int)(Fact(max + 1, min + max) / Fact(1, min));
+    }
+
+    private BigInteger Fact(int start, int end)
+    {
+        BigInteger res = start;
+        while (++start <= end)
+            res *= start;
+        return res;
+    }
+}