Description
Scramble a caller-selected solved grid by legal blank moves with complete replay and inverse moves, preserving reachability without a minimum-distance guarantee.
A generated practice exercise contains a prompt and an answer key under a specific rule set. A planted answer establishes one possible solution; only an explicit enumeration or uniqueness check establishes whether alternatives exist.
Scramble a caller-selected solved grid by legal blank moves with complete replay and inverse moves, preserving reachability without a minimum-distance guarantee.
When to use this tool
Use this generator to create reproducible sliding tile scramble cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.
How to use the tool and how it works
- Supply solvedBoard, moveCount in the field shapes below. Set seed when you need an explicit replay.
- Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
- Read initialBoard, moves, finalBoard, inverseMoves. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.
Starting from the caller-designated solved board, repeatedly choose a legal orthogonal move of the zero blank. Record the moved tile, flattened zero-based blank positions, and board snapshot, then reverse and invert the directions to provide a return sequence.1
Delegated operations used for this result: reshape. Their calculation or parsing conventions apply to the corresponding result fields.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| solvedBoard | Solved Board | Required. Array of Array of Safe integer; minimum 0.; minimum items 2; maximum items 8.; minimum items 2; maximum items 8. |
| moveCount | Move Count | Required. Safe integer; minimum 0; maximum 128. |
| seed | Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed. | Optional. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| initialBoard | Initial Board | Required. Array of Array of Safe integer; minimum 0.; minimum items 2; maximum items 8.; minimum items 2; maximum items 8. |
| moves | Moves | Required. Array of Object; no unknown keys.; minimum items 0; maximum items 128. |
| moves[].direction | Direction | Required. Text; one of "up", "down", "left", "right". |
| moves[].tile | Tile | Required. Safe integer. |
| moves[].blankFrom | Blank From | Required. Safe integer. |
| moves[].blankTo | Blank To | Required. Safe integer. |
| moves[].board | Board | Required. Array of Array of Safe integer; minimum 0.; minimum items 2; maximum items 8.; minimum items 2; maximum items 8. |
| finalBoard | Final Board | Required. Array of Array of Safe integer; minimum 0.; minimum items 2; maximum items 8.; minimum items 2; maximum items 8. |
| inverseMoves | Inverse Moves | Required. Array of Text; one of "up", "down", "left", "right".; minimum items 0; maximum items 128. |
| randomness | Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source. | Required. Object; no unknown keys. |
| randomness.seed | Optional numeric replay seed; normalization and precedence are explained below. | Required. Safe integer. or Null. |
| randomness.source | Source | Required. Text; one of "context", "seed". |
An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.
{
"input": {
"solvedBoard": [
[
1,
2
],
[
3,
0
]
],
"moveCount": 3,
"seed": 42
},
"output": {
"initialBoard": [
[
1,
2
],
[
3,
0
]
],
"moves": [
{
"direction": "left",
"tile": 3,
"blankFrom": 3,
"blankTo": 2,
"board": [
[
1,
2
],
[
0,
3
]
]
},
{
"direction": "up",
"tile": 1,
"blankFrom": 2,
"blankTo": 0,
"board": [
[
0,
2
],
[
1,
3
]
]
},
{
"direction": "right",
"tile": 2,
"blankFrom": 0,
"blankTo": 1,
"board": [
[
2,
0
],
[
1,
3
]
]
}
],
"finalBoard": [
[
2,
0
],
[
1,
3
]
],
"inverseMoves": [
"left",
"down",
"right"
],
"randomness": {
"seed": 42,
"source": "seed"
}
}
}Limitations and assumptions
- The board must be rectangular with distinct nonnegative values and exactly one zero. Immediate reversals and repeated states are allowed. Move count does not establish distance from the starting board or puzzle difficulty.
- A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
- The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.
Alternative or Complementary methods
For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.
References
Similar or alternative tools
- Random Inference Rule Proof Cards Generator
Compose formal modus ponens, modus tollens, and hypothetical syllogism cards with fresh illustrative atoms and controlled invalid conclusions, delegating rule keys.
- Random Integer Partition Matching Puzzle Generator
Construct bounded positive or nonnegative integer compositions and optional canonical unordered partitions, retaining exact sum and conventions.