exercism 76 List Ops

Author: kumar91gopi

README.md

@@ -297,6 +297,7 @@ solution of many challenges of [Leetcode](https://leetcode.com/), [Exercism](htt
 73. [Secret Handshake](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/secret_handshake.rb)
 74. [Atbash Cipher](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/atbash_cipher.rb)
 75. [Crypto Square](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/crypto_square.rb)
+76. [List Ops](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/list_ops.rb)
 
 <a name="leetcode"/>
 

exercism/list-ops.rb

@@ -0,0 +1,70 @@
+# Problem: https://exercism.org/tracks/ruby/exercises/list-ops
+
+# Solution
+class ListOps
+    def self.arrays(arr)
+      len=0
+      arr.each do |x|
+        len+=1
+      end
+      len
+    end
+
+    def self.reverser(arr)
+       return [] if arr==[]
+      len = self.arrays(arr)
+      i=0
+      j=len-1
+      while i<j
+        arr[i],arr[j] = arr[j],arr[i]
+        i+=1
+        j-=1
+      end
+      arr
+    end
+
+    def self.concatter(arr1,arr2)
+      return arr1||arr2 if arr1==[] || arr2==[]
+      arr2.each do |num|
+        arr1.append(num)
+      end
+      arr1
+    end
+
+    def self.mapper(arr,&block)
+      return [] if arr==[]
+      new_arr=[]
+      arr.each do |x|
+        val=block.call(x)
+        new_arr.append(val)
+      end
+    new_arr
+    end
+
+    def self.filterer(arr,&block)
+      return [] if arr==[]
+      new_arr=[]
+      arr.each do |x|
+          new_arr.append(x) if block.call(x)
+      end
+    new_arr
+    end
+
+    def self.sum_reducer(arr)
+      return 0 if arr==[]
+      sum=0
+      arr.each do |x|
+          sum+=x
+      end
+    sum
+    end
+
+    def self.factorial_reducer(arr)
+      return 1 if arr==[]
+      factorial=1
+      arr.each do |x|
+          factorial*=x
+      end
+    factorial
+    end    
+  end