Exchange Cups

Problem Overview

• Given N cups labeled 1..N and their current order, compute the minimum number of pair swaps needed to sort them to 1..N.
• Input: N (N < 10000) and a sequence of N positive integers; Output: one integer, the least swap count.
• Real-world context: reorganizing items on a store shelf using two-at-a-time exchanges.
• From TikTok interviews; a coding interview problem often presented as an interview question on arrays and permutations.