Run Sum
Count each digit once when a neighbour along the line differs by 1. These digits add up to the clue.
Parameters
| Parameter | Meaning | Default |
|---|---|---|
| cells | The marked cells, for example r1c1-r1c2-r2c2. | Required. |
| sum | The total the digits or values must add up to. | Required. |
Maths
Class: with aggregates.
The shared predicates define the notation and every named predicate.
countRun(cells)=sum
Sum each position once when at least one neighbouring position on the line differs by exactly 1. This sum equals sum.
Example
---
format: open-rules
title: Run Sum example
setter: Example
source: ""
case: ""
library: https://rules.sudoku-sleuth.com/
status: read
---
```rules
sudoku 9x9
run-sum r1c1-r1c2-r1c3 sum 6
```
Satisfies the rule: r1c1=1, r1c2=2, r1c3=3. All three consecutive-run digits contribute to total 6.
Breaks the rule: r1c1=1, r1c2=2, r1c3=5. A digit outside the run leaves the wrong contributing total.