Calculate the Sum

Problem Overview

• Apply inclusive range toggles to a row of switches (all start off) and compute the sum of indices that end up on.
• Input: n operations and a 2D array of [left, right] indices (1-based); Output: integer sum of on switch indices.
• Context: models NOT operations on consecutive two-position switches in a simple electrical row.
• From Expedia interviews; this problem is a common coding interview interview question.