Integer_palindrome_check - Divya

lib/integer_palindrome_check.rb

@@ -1,4 +1,41 @@
 # Returns true if the input positive integer number forms a palindrome. Returns false otherwise.
+# A method to check if the input string is a palindrome.
+# Return true if the string is a palindrome. Return false otherwise.
+# Time complexity - O(n/2) --> O(n)
+# Space complexity is a CONSTANT as the pointer for the variable storing the
+# number is changing but not extra space is occupied by the changing values.
 def is_palindrome(number)
-  raise NotImplementedError
-end
+
+    if number == nil || number < 0
+      return false
+    end
+
+    length = 0
+    counter = number
+
+    while counter >= 10
+      counter /= 10
+      length += 1
+    end
+
+    index = 0
+    first_index = 0
+    last_index = length - 1
+
+    check = true
+    while index < length
+
+      # palindrome check
+      first_digit = number / (10 ** (length-(index)))
+      # removes first digit
+      number = number - (first_digit * (10 ** (length-index)))
+      last_digit = number % (10)
+      # removes last digit
+      number = number / 10
+      if first_digit != last_digit
+        check = false
+      end
+      index += 2
+    end
+    return check
+  end