Get Maximum Sum

Problem Overview

• Select exactly x elements from an n x n matrix to maximize the sum, with at most factor[i] taken from row i; return -1 if impossible.
• Inputs: factor[n], data[n][n], x. Output: maximum sum (long integer) or -1.
• Constraints: n <= 1000, data[i][j] <= 1e9, 1 <= factor[i] <= n.
• Real-world context: Amazon prototype for matrix compression; an Amazon interviews coding interview problem and interview question.