Open Rules

Lockout

The end digits differ by at least the stated gap. Every digit between them is below both ends or above both ends.

Parameters

Parameter Meaning Default
ends The two end cells, in their stated order. Required.
line The cells in order, for example r1c1-r1c2-r1c3. Required.
gap The least difference between the two end digits. Required.

Maths

Class: first-order.

The shared predicates define the notation and every named predicate.

|ends|=2 ∧ |D(ends[0])-D(ends[1])|>=gap ∧ ∀c∈line: D(c)<minimumPair(D(ends[0]),D(ends[1])) ∨ D(c)>maximumPair(D(ends[0]),D(ends[1]))

The endpoint digits differ by at least gap. Every interior digit is strictly below both ends or strictly above both ends.

Example

---
format: open-rules
title: Lockout example
setter: Example
source: ""
case: ""
library: https://rules.sudoku-sleuth.com/
status: read
---

```rules
sudoku 9x9
lockout r1c2 ends ["r1c1","r1c3"] gap 4
```

Satisfies the rule: r1c2=1, r1c1=2, r1c3=7. The ends differ by 5, and 1 is below both ends.

Breaks the rule: r1c2=4, r1c1=2, r1c3=7. 4 lies between the end digits.