Clear the Grid: Sum to 15

Overview

Implement a card grid game where you repeatedly find and remove triples of cards that sum to 15.

Given a rectangular grid of integers, find three distinct cells whose values sum to 15, remove them, redeal the remaining cards into the grid (row-major order), and repeat until no valid moves remain.

Rules

• A move selects 3 distinct cells whose values sum to 15.
• When multiple valid triples exist, pick the one whose sorted coordinate list is lexicographically smallest.
• After removing 3 cards, redeal the remaining cards row-major into the grid.
• Stop when no valid move exists.
• Raise ValueError for invalid input: empty grid, empty rows, ragged grid, or non-integer values.

Scoring

Each test case is worth equal points. Final score is the percentage of passing tests.