Sumplete · strategies
Extremes first, then lock.
Every cell is either kept or deleted. The targets constrain which subsets are possible — and most lines have very few.
Full lines
If a row's target equals the sum of all its cells, keep everything — nothing to delete. If a column's target is achievable only one way, mark the rest immediately.
Single-cell elimination
If removing one specific cell makes the row's remaining sum match the target exactly, and the column still works too — that cell is deleted. Scan for single-removals first.
Cross-referencing row + column
A cell sits in one row and one column. If keeping it makes EITHER target impossible, it's deleted. If deleting it makes either impossible, it's kept. Test one cell at a time.
Forced keeps from running totals
As you delete cells, the remaining sum in that line drops. When it equals the target, every remaining unmarked cell in the line is kept (deleting more would undershoot).
Order of attack
Full lines → single-removal scans → cross-reference stuck cells → forced-keep locks. Cycle until done. Our puzzles are always deduction-solvable.