Amazon SDE intern OA experience

I had attended an Amazon SDE intern interview on 17/03/2026 (on campus) and these were the 2 questions I got

Question 1: Warehouse Robots with Threshold

Problem Description
You are given an integer array arr of size n, where arr[i] represents the threshold of the i-th robot.
Each robot can be assigned one of two states:
Running
Waiting
A configuration is valid if all robots satisfy the following conditions:
If a robot is Running, then the total number of running robots must be ≥ arr[i]
If a robot is Waiting, then the total number of waiting robots must be < arr[i]

Task
Return the total number of valid configurations.

Constraints
Each robot must be assigned exactly one state.
A configuration is valid only if no robot violates its condition.

Question 2: Most Common Product Pair

Problem Description
You are given a list of transactions, where each transaction is a list of products purchased together.
[
['A','B','C'],
['A','B'],
['C','B'],
['A','B'],
['A','C']
]

Task
Return the pair of products that appears together most frequently across all transactions.

Rules
A pair consists of exactly two distinct products.
(A, B) and (B, A) are considered the same pair.
If multiple pairs have the same highest frequency, return the lexicographically smallest pair.

Notes
Duplicate items within a transaction should be counted only once.
Each transaction can contribute multiple pairs.