old_contents: # Time:  O(n)
  # Space: O(1)
  #
  # Given an array of integers that is already sorted in ascending order, 
  # find two numbers such that they add up to a specific target number.
  # 
  # The function twoSum should return indices of the two numbers such that 
  # they add up to the target, where index1 must be less than index2. 
  # Please note that your returned answers (both index1 and index2) are not zero-based.
  # 
  # You may assume that each input would have exactly one solution.
  # 
  # Input: numbers={2, 7, 11, 15}, target=9
  # Output: index1=1, index2=2
  #
  
  class Solution:
      def twoSum(self, nums, target):
          start, end = 0, len(nums) - 1
          
          while start != end:
              if nums[start] + nums[end] > target:
                  end -= 1
              elif nums[start] + nums[end] < target:
                  start += 1
              else:
                  return [start + 1, end + 1]
  
  if __name__ == "__main__":
      print Solution().twoSum([2, 7, 11, 15], 9)
new_contents: # Time:  O(n)
  # Space: O(1)
  #
  # Given an array of integers that is already sorted in ascending order, 
  # find two numbers such that they add up to a specific target number.
  # 
  # The function twoSum should return indices of the two numbers such that 
  # they add up to the target, where index1 must be less than index2. 
  # Please note that your returned answers (both index1 and index2) are not zero-based.
  # 
  # You may assume that each input would have exactly one solution.
  # 
  # Input: numbers={2, 7, 11, 15}, target=9
  # Output: index1=1, index2=2
  #
  
  class Solution:
      def twoSum(self, nums, target):
          start, end = 0, len(nums) - 1
          
          while start != end:
              sum = nums[start] + nums[end]
              if sum > target:
                  end -= 1
              elif sum < target:
                  start += 1
              else:
                  return [start + 1, end + 1]
  
  if __name__ == "__main__":
      print Solution().twoSum([2, 7, 11, 15], 9)
  
subject: Update two-sum-ii-input-array-is-sorted.py