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

Solution Notebook¶

Problem: Maximizing XOR¶

See the HackerRank problem page.

Constraints
Test Cases
Algorithm
Code
Unit Test

Constraints¶

See the HackerRank problem page.

Test Cases¶

See the HackerRank problem page.

Algorithm¶

Set max to 0
For i in the range (lower, upper) inclusive
- For j in the range (lower, upper) inclusive
  - Compare i ^ j with max, update max if needed
return max

Complexity:

Time: O(n^2) - See note below
Space: O(1)

Note:

TODO: Add more optimal solutions such as those discussed here.

Code¶

In [1]:

class Solution(object):

    def max_xor(self, lower, upper):
        result = 0
        for l in range(lower, upper + 1):
            for u in range(lower, upper + 1):
                curr = l ^ u
                if result < curr:
                    result = curr
        return result

Unit Test¶

In [2]:

%%writefile test_maximizing_xor.py
import unittest


class TestMaximizingXor(unittest.TestCase):

    def test_maximizing_xor(self):
        solution = Solution()
        self.assertEqual(solution.max_xor(10, 15), 7)
        print('Success: test_maximizing_xor')


def main():
    test = TestMaximizingXor()
    test.test_maximizing_xor()


if __name__ == '__main__':
    main()

Overwriting test_maximizing_xor.py

In [3]:

%run -i test_maximizing_xor.py

Success: test_maximizing_xor