Move to a different file since the input is sorted by default

data_structures/arrays/two_sum.rb

@@ -131,49 +131,3 @@ nums = [3, 3]
 target = 6
 print(two_sum(nums, target))
 # => [0,1]
-
-#
-# Approach 4: Two pointers
-#
-
-# Complexity analysis
-
-# Time complexity: O(n). Each of the n elements is visited at
-# most once, thus the time complexity is O(n).
-
-# Space complexity: O(1). We only use two indexes, the space
-# complexity is O(1).
-
-def two_sum(numbers, target)
-  i = 0
-  j = numbers.length - 1
-  # note: sorting the array is important
-  numbers = numbers.sort
-
-  while i < j
-    sum = numbers[i] + numbers[j]
-
-    if target < sum
-      j -= 1
-    elsif target > sum
-      i += 1
-    else
-      return [i, j]
-    end
-  end
-end
-
-nums = [2, 7, 11, 15]
-target = 9
-print(two_sum(nums, target))
-# => [0,1]
-
-nums = [2, 3, 4]
-target = 6
-print(two_sum(nums, target))
-# => [0,2]
-
-nums = [-1, 0]
-target = -1
-print(two_sum(nums, target))
-# => [0,1]

data_structures/arrays/two_sum_ii.rb

@@ -0,0 +1,49 @@
+# Given an array of integers numbers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.
+
+# Return the indices of the two numbers (1-indexed) as an integer array answer of size 2, where 1 <= answer[0] < answer[1] <= numbers.length.
+
+# You may assume that each input would have exactly one solution and you may not use the same element twice.
+
+#
+# Approach 1: Two pointers
+#
+
+# Complexity analysis
+
+# Time complexity: O(n). Each of the n elements is visited at
+# most once, thus the time complexity is O(n).
+
+# Space complexity: O(1). We only use two indexes, the space
+# complexity is O(1).
+
+def two_sum(numbers, target)
+  i = 0
+  j = numbers.length - 1
+
+  while i < j
+    sum = numbers[i] + numbers[j]
+
+    if target < sum
+      j -= 1
+    elsif target > sum
+      i += 1
+    else
+      return [i, j]
+    end
+  end
+end
+
+nums = [2, 7, 11, 15]
+target = 9
+print(two_sum(nums, target))
+# => [0,1]
+
+nums = [2, 3, 4]
+target = 6
+print(two_sum(nums, target))
+# => [0,2]
+
+nums = [-1, 0]
+target = -1
+print(two_sum(nums, target))
+# => [0,1]