data_structures.arrays.prefix_sum
=================================

.. py:module:: data_structures.arrays.prefix_sum

.. autoapi-nested-parse::

   Author  : Alexander Pantyukhin
   Date    : November 3, 2022

   Implement the class of prefix sum with useful functions based on it.



Classes
-------

.. autoapisummary::

   data_structures.arrays.prefix_sum.PrefixSum


Module Contents
---------------

.. py:class:: PrefixSum(array: list[int])

   .. py:method:: contains_sum(target_sum: int) -> bool

      The function returns True if array contains the target_sum,
      False otherwise.

      Runtime : O(n)
      Space: O(n)

      >>> PrefixSum([1,2,3]).contains_sum(6)
      True
      >>> PrefixSum([1,2,3]).contains_sum(5)
      True
      >>> PrefixSum([1,2,3]).contains_sum(3)
      True
      >>> PrefixSum([1,2,3]).contains_sum(4)
      False
      >>> PrefixSum([1,2,3]).contains_sum(7)
      False
      >>> PrefixSum([1,-2,3]).contains_sum(2)
      True



   .. py:method:: get_sum(start: int, end: int) -> int

      The function returns the sum of array from the start to the end indexes.
      Runtime : O(1)
      Space: O(1)

      >>> PrefixSum([1,2,3]).get_sum(0, 2)
      6
      >>> PrefixSum([1,2,3]).get_sum(1, 2)
      5
      >>> PrefixSum([1,2,3]).get_sum(2, 2)
      3
      >>> PrefixSum([]).get_sum(0, 0)
      Traceback (most recent call last):
      ...
      ValueError: The array is empty.
      >>> PrefixSum([1,2,3]).get_sum(-1, 2)
      Traceback (most recent call last):
      ...
      ValueError: Invalid range specified.
      >>> PrefixSum([1,2,3]).get_sum(2, 3)
      Traceback (most recent call last):
      ...
      ValueError: Invalid range specified.
      >>> PrefixSum([1,2,3]).get_sum(2, 1)
      Traceback (most recent call last):
      ...
      ValueError: Invalid range specified.



   .. py:attribute:: prefix_sum