Math with Lego Blocks

Problem Overview

• Replace zeros in two rows so their sums are equal and as small as possible.
• Input: arrays rowA (n) and rowB (m) with positive integers and zeros for missing; Output: minimum achievable equal sum or -1 if impossible.
• Constraints: 1 ≤ n,m ≤ 1e5; values in [0,10^4]; replacements must be positive.
• Real-world context: teaching math with Lego blocks in a classroom.
• From Citadel interviews; a coding interview problem and interview question.