Distribute Elements Into Two Arrays I

Distribute Elements Into Two Arrays I

What is this problem about?

In the Distribute Elements Into Two Arrays I coding problem, you are given an array of integers. You need to distribute these elements into two new arrays, arr1 and arr2, following a specific rule. The first element goes to arr1, the second to arr2. For every subsequent element, you compare the last element of arr1 with the last element of arr2. If the last element of arr1 is greater, the new element goes to arr1; otherwise, it goes to arr2. Finally, concatenate arr1 and arr2.

Why is this asked in interviews?

This "Easy" problem is used by Autodesk and Amazon to test basic Simulation interview patterns. It evaluates whether a candidate can follow procedural instructions and correctly manage dynamic lists. It’s a test of code clarity and accuracy in implementing a logic-based distribution process.

Algorithmic pattern used

This is a simple Simulation problem.

1. Initialize two dynamic lists (or arrays), arr1 and arr2.
2. Add nums[0] to arr1 and nums[1] to arr2.
3. Iterate from index 2 to $n-1$.
4. Apply the comparison rule using the current element and the tails of the two arrays.
5. Join the arrays and return.

Example explanation

nums = [5, 4, 3, 8]

1. arr1 = [5], arr2 = [4].
2. Next is 3. arr1.last (5) > arr2.last (4). Add 3 to arr1. arr1 = [5, 3].
3. Next is 8. arr1.last (3) < arr2.last (4). Add 8 to arr2. arr2 = [4, 8]. Result: [5, 3, 4, 8].

Common mistakes candidates make

• Index errors: Starting the loop from 0 or 1 instead of 2.
• Wrong Comparison: Comparing the sums of the arrays instead of just the last elements.
• Inefficient Concatenation: Not realizing that the final result is just the two lists appended together.

Interview preparation tip

For simulation problems, focus on readability. Use clear names like last1 and last2 to make your code easy to follow. Simple problems are often used to see how "cleanly" you code.