refactor: refactor project structure

legacy/2787 numberOfWays/C#/Program.cs

@@ -0,0 +1,48 @@
+// knapsack problem
+public class Solution
+{
+    public int NumberOfWays(int n, int x)
+    {
+        const int MOD = 1_000_000_007;
+        // list all the powers which smaller than n
+        var powers = new List<int>();
+        var num = 1;
+
+        while (true)
+        {
+            int pow = (int)Math.Pow(num, x);
+            if (pow > n)
+                break;
+            powers.Add(pow);
+            num++;
+        }
+
+        // dynamic programming
+        var dp = new int[n + 1];
+        dp[0] = 1;
+
+        foreach (var power in powers)
+        {
+            for (var i = n; i >= power; i--)
+            {
+                dp[i] = (dp[i] + dp[i - power]) % MOD;
+            }
+        }
+
+        return dp[n];
+
+    }
+
+}
+
+class Program
+{
+    static void Main()
+    {
+        var solution = new Solution();
+
+        Console.WriteLine(solution.NumberOfWays(4, 1));
+        Console.WriteLine(solution.NumberOfWays(100, 3));
+
+    }
+}