This notebook was prepared by Donne Martin. Source and license info is on GitHub.

Challenge Notebook

Problem: Sum of Two Integers.

See the LeetCode problem page.


  • Can we assume we're working with 32 bit ints?
    • Yes
  • Can we assume the inputs are valid?
    • No, check for None
  • Can we assume this fits memory?
    • Yes

Test Cases

See the LeetCode problem page.


Refer to the Solution Notebook. If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.


In [ ]:
class Solution(object):

    def sum_two(self, val):
        # TODO: Implement me

Unit Test

The following unit test is expected to fail until you solve the challenge.

In [ ]:
# %load
import unittest

class TestSumTwo(unittest.TestCase):

    def test_sum_two(self):
        solution = Solution()
        self.assertRaises(TypeError, solution.sum_two, None)
        self.assertEqual(solution.sum_two(5, 7), 12)
        self.assertEqual(solution.sum_two(-5, -7), -12)
        self.assertEqual(solution.sum_two(5, -7), -2)
        print('Success: test_sum_two')

def main():
    test = TestSumTwo()

if __name__ == '__main__':

Solution Notebook

Review the Solution Notebook for a discussion on algorithms and code solutions.