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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var assert = require('assert');

​

function kLargest(nums, k) {

  // fill in

  return nums;

}

​

try {

  assertSameMembers(kLargest([5, 16, 7, 9, -1, 4, 3, 11, 2], 3), [9, 11, 16]);

​

  console.log(

    'PASSED: `kLargest([5, 16, 7, 9, -1, 4, 3, 11, 2], 3)` returns `[9, 11, 16]`'

  );

} catch (err) {

  console.log(err);

}

​

try {

  assertSameMembers(

    kLargest([29, 17, 9, -1, -3, 11, 2], 6),

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

  );

​

  console.log(

    'PASSED: `kLargest([29, 17, 9, -1, -3, 11, 2], 6)` returns `[29, 17, 11, 9, 2, -1]`'

  );

} catch (err) {

  console.log(err);

}

Here's our guided, illustrated walk-through.

How do I use this guide?