summary.md

Answer summary for interview

Answer structure

1. Restate the problem to confirm understanding.
2. Explain the key idea or insight needed to solve the problem.
3. Describe the algorithm or approach step-by-step.
4. Analyze time and space complexity.
5. Provide an example to illustrate the solution.

Answer example

Let me restate the problem first. We need to find a contiguous subarray that gives the largest product. The array may contain positive, negative, and zero values.

The key idea is that the product can flip its sign when multiplied by a negative number. So we need to keep track of both the maximum and minimum product up to each index.

For each number nums[i], we update: (we can write the following equations)

maxProd = max(nums[i], nums[i] * prevMax, nums[i] * prevMin)
minProd = min(nums[i], nums[i] * prevMax, nums[i] * prevMin)

Then we keep a global result that stores the maximum maxProd so far.

This takes linear time O(n) and constant space O(1).

For example, given [2,3,-2,4], the answer is 6.”

(Pause) “Does that make sense?”