From 5732efb4a4a95692faebbba554b6fe22fa18fd5e Mon Sep 17 00:00:00 2001
From: Aman Sharma <amsharma44@outlook.com>
Date: Wed, 17 Oct 2018 16:20:55 +0530
Subject: [PATCH] Coin Change solution

---
 coin-change.cs      | 57 +++++++++++++++++++++++++++++++++++++++++++++
 string-reduction.cs | 50 ---------------------------------------
 2 files changed, 57 insertions(+), 50 deletions(-)
 create mode 100644 coin-change.cs
 delete mode 100644 string-reduction.cs

diff --git a/coin-change.cs b/coin-change.cs
new file mode 100644
index 00000000..708ad28d
--- /dev/null
+++ b/coin-change.cs
@@ -0,0 +1,57 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using System.Text;
+using System.Numerics;
+using System.Diagnostics;
+
+namespace ConsoleApplication
+{
+
+    class Program
+    {
+        public static long[,] dp = new long[52, 252];
+
+        public static void Main(String[] args)
+        {
+            int[] l0 = Array.ConvertAll<string, int>(Console.ReadLine().Trim().Split(' '), e => int.Parse(e));
+            int[] coins = Array.ConvertAll<string, int>(Console.ReadLine().Trim().Split(' '), e => int.Parse(e));
+            int sum = l0[0];
+            int n = l0[1];
+            for(int i = 0; i < 52; i++)
+            {
+                for(int j = 0; j < 252; j++)
+                {
+                    dp[i, j] = -1;
+                }
+            }
+
+            Console.WriteLine(calculate(coins, sum, n - 1, 0));
+        }
+
+        public static long calculate(int[] coins, int sum, int numCoin, int i)
+        {
+            if(sum == 0)
+            {
+                return 1;
+            }
+
+            if(sum < 0)
+            {
+                return 0;
+            }
+
+            if(i > numCoin)
+            {
+                return 0;
+            }
+
+            if(dp[i, sum] == -1)
+            {
+                dp[i, sum] = calculate(coins, sum, numCoin, i + 1) + calculate(coins, sum - coins[i], numCoin, i);
+            }
+
+            return dp[i, sum];
+        }
+    }
+}
\ No newline at end of file
diff --git a/string-reduction.cs b/string-reduction.cs
deleted file mode 100644
index 671d8477..00000000
--- a/string-reduction.cs
+++ /dev/null
@@ -1,50 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
-class Solution {
-
-    static int stringReduction (string a) {
-        int[] ar = new int[3];
-            for(int i = 0; i < a.Length; i++)
-            {
-                if(a[i] == 'a')
-                {
-                    ar[0]++;
-                }else if(a[i] == 'b')
-                {
-                    ar[1]++;
-                }
-                else
-                {
-                    ar[2]++;
-                }
-            }
-
-            if((ar[0] == 0 && ar[1] == 0) || (ar[1]== 0 && ar[2] == 0)||(ar[0] == 0 && ar[2] == 0))
-            {
-                return a.Length;
-            }
-
-            if ((ar[0] % 2 == 0 && ar[1] %2== 0) && (ar[1] %2 == 0 && ar[2] %2== 0))
-            {
-                return 2;
-            }
-
-            if ((ar[0] % 2 == 1 && ar[1] % 2 == 1) && (ar[1] % 2 == 1 && ar[2] % 2 == 1))
-            {
-                return 2;
-            }
-
-            return 1;
-    }
-
-    static void Main(String[] args) {
-        int res;
-        int _t_cases = Convert.ToInt32(Console.ReadLine());
-        for (int _t_i=0; _t_i<_t_cases; _t_i++) {
-            String _a = Console.ReadLine();
-            res=stringReduction(_a);
-            Console.WriteLine(res);
-        }
-    }
-}