Random No-Repeat Playlist Cycle Generator

Description

Construct supplied-content playlists with exact cooldowns, optional bank-exhaustion cycles, total-play caps, and bounded randomized feasibility search.

Sampling selects from a supplied population under rules for replacement, grouping, or eligibility. Draw probabilities, inclusion probabilities, and repeat counts describe different aspects of selection; a reproducible sample is not automatically representative of a real population.

Construct supplied-content playlists with exact cooldowns, optional bank-exhaustion cycles, total-play caps, and bounded randomized feasibility search.

When to use this tool

Use this generator to create reproducible no repeat playlist cycle 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 items, count, history, itemCooldown, categoryCooldown, maxPlaysPerItem, cyclePolicy, feasibilityPolicy 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 playlist, complete, frequencies, finalHistory. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.

Validate supplied history against play quotas, item/category cooldowns, and optional exhaust-bank cycles. Use bounded backtracking to extend the playlist, either requiring a full result or returning the longest feasible prefix; return counts and updated history.^[1]

Input field	Meaning and units	Accepted input
items	Items	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32.
items[].id	Literal identifier used to match records, independently of their display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
items[].category	Category	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
items[].content	Content	Required. Text; maximum UTF-16 length 4096.
count	Requested count; the mechanics explain whether one draw expands into several returned records.	Required. Safe integer; minimum 0; maximum 64.
history	History	Required. Array of Text; minimum UTF-16 length 1; maximum UTF-16 length 128.; minimum items 0; maximum items 128.
itemCooldown	Item Cooldown	Required. Safe integer; minimum 0; maximum 128.
categoryCooldown	Category Cooldown	Required. Safe integer; minimum 0; maximum 128.
maxPlaysPerItem	Max Plays Per Item	Required. Safe integer; minimum 1.
cyclePolicy	Cycle Policy	Required. Text; one of "exhaust-bank", "cooldown".
feasibilityPolicy	Search all branches within 20000 visits; longest-prefix returns a proven longest prefix only after exhaustive search.	Required. Text; one of "require-full", "longest-prefix".
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
playlist	Playlist	Required. Array of Object; no unknown keys.; minimum items 0; maximum items 64.
playlist[].item	Item	Required. Object; no unknown keys.
playlist[].item.id	Literal identifier used to match records, independently of their display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
playlist[].item.category	Category	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
playlist[].item.content	Content	Required. Text; maximum UTF-16 length 4096.
playlist[].cycle	Cycle	Required. Safe integer; minimum 0.
complete	Complete	Required. Boolean.
frequencies	Frequencies	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32.
frequencies[].itemId	Item Id	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
frequencies[].newPlays	New Plays	Required. Safe integer; minimum 0.
frequencies[].totalPlays	Total Plays	Required. Safe integer; minimum 0.
finalHistory	Final History	Required. Array of Text; minimum UTF-16 length 1; maximum UTF-16 length 128.; minimum items 0; maximum items 192.
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.

json

{
  "input": {
    "items": [
      {
        "id": "a",
        "category": "strings",
        "content": "Dawn"
      },
      {
        "id": "b",
        "category": "keys",
        "content": "Rain"
      },
      {
        "id": "c",
        "category": "strings",
        "content": "Dusk"
      }
    ],
    "count": 5,
    "history": [],
    "itemCooldown": 1,
    "categoryCooldown": 0,
    "maxPlaysPerItem": 2,
    "cyclePolicy": "exhaust-bank",
    "feasibilityPolicy": "require-full",
    "seed": 42
  },
  "output": {
    "playlist": [
      {
        "item": {
          "id": "b",
          "category": "keys",
          "content": "Rain"
        },
        "cycle": 1
      },
      {
        "item": {
          "id": "a",
          "category": "strings",
          "content": "Dawn"
        },
        "cycle": 1
      },
      {
        "item": {
          "id": "c",
          "category": "strings",
          "content": "Dusk"
        },
        "cycle": 1
      },
      {
        "item": {
          "id": "b",
          "category": "keys",
          "content": "Rain"
        },
        "cycle": 2
      },
      {
        "item": {
          "id": "a",
          "category": "strings",
          "content": "Dawn"
        },
        "cycle": 2
      }
    ],
    "complete": true,
    "frequencies": [
      {
        "itemId": "a",
        "newPlays": 2,
        "totalPlays": 2
      },
      {
        "itemId": "b",
        "newPlays": 2,
        "totalPlays": 2
      },
      {
        "itemId": "c",
        "newPlays": 1,
        "totalPlays": 1
      }
    ],
    "finalHistory": [
      "b",
      "a",
      "c",
      "b",
      "a"
    ],
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

The search is not uniform over valid playlists. Past violations are rejected. complete can be false under the partial policy, and search-budget exhaustion is distinct from a proven global infeasibility result.
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

Tool behavior and example: Random No-Repeat Playlist Cycle Generator — tool.io

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