Good morning! Here's our prompt for today.

We're given a list or array of numbers, like the following:

const nums = [5, 16, 7, 9, -1, 4, 3, 11, 2]

Can you write an algorithm to find the k largest values in a list of n elements? If k were 3, we'd want the three largest numbers returned. The correct logic would return [16, 11, 9]. Order is not a consideration.

Can you find more than one approach to this problem?

Constraints

• Length of the array <= 100000
• The array will contain values between -1000000000 and 1000000000
• The final answer will always fit in the integer range
• Expected time complexity : O(n logk) where k is the size of the heap
• Expected space complexity : O(k)

Try to solve this here or in Interactive Mode.

How do I practice this challenge?

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def k_largest(nums, k):

    # fill in

    return k_lgst_nums

​

​

import unittest

​

​

class Test(unittest.TestCase):

    def test_1(self):

        assert sorted(k_largest([5, 16, 7, 9, -1, 4, 3, 11, 2], 3)) == sorted(

            [9, 11, 16]

        )

        print(

            "PASSED: assert `k_largest([5, 16, 7, 9, -1, 4, 3, 11, 2], 3)` returns `[9, 11, 16]`"

        )

​

    def test_2(self):

        assert sorted(k_largest([29, 17, 9, -1, -3, 11, 2], 6)) == sorted(

            [29, 17, 11, 9, 2, -1]

        )

        print(

            "PASSED: assert `k_largest([29, 17, 9, -1, -3, 11, 2], 6)` returns `[29, 17, 11, 9, 2, -1]`"

        )

​

​

if __name__ == "__main__":

    unittest.main(verbosity=2)

    print("Nice job, 2/2 tests passed!")

Here's our guided, illustrated walk-through.

How do I use this guide?