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kahgohkahgoh
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Add sieve exercise (#514)
* Add sieve exercise * Update to use template
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-17
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14 files changed

+207
-17
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‎config.json

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"solution": [
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"%{snake_slug}.ml"
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],
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"editor": [
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"%{snake_slug}.mli"
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],
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"test": [
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"test.ml"
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],
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],
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"exemplar": [
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".meta/exemplar.ml"
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],
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"editor": [
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"%{snake_slug}.mli"
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]
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},
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"exercises": {
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"concept": [],
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"practice": [
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{
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"slug": "hexadecimal",
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"practices": [],
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"prerequisites": [],
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"difficulty": 1,
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"topics": null,
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"status": "deprecated"
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},
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{
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"uuid": "dd066b62-c63e-467c-8dfb-435bcc81d532",
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"practices": [],
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"prerequisites": [],
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"difficulty": 2,
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"topics": null
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"difficulty": 2
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},
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{
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"slug": "reverse-string",
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"uuid": "a43c28f4-8f5c-40f7-90cb-79689c810f95",
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"practices": [],
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"prerequisites": [],
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"difficulty": 3,
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"topics": []
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"difficulty": 3
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},
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{
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"slug": "all-your-base",
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"uuid": "8d21e4be-5e9c-4c73-81c5-b4ee2517d9c7",
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"practices": [],
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"prerequisites": [],
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"difficulty": 4,
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"topics": []
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"difficulty": 4
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},
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{
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"slug": "matching-brackets",
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"topics": [
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"functional_programming"
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]
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},
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{
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"slug": "sieve",
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"name": "Sieve",
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"uuid": "8157f71a-25ca-476c-8ac8-dcf660e5193b",
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"practices": [],
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"prerequisites": [],
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"difficulty": 2
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}
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]
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},
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"concepts": [],
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"key_features": [
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{
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"title": "Algebraic data types",
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}
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],
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"tags": [
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"paradigm/functional",
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"typing/static",
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"typing/strong",
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"execution_mode/compiled",
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"platform/windows",
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"platform/mac",
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"paradigm/functional",
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"platform/linux",
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"platform/mac",
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"platform/windows",
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"runtime/language_specific",
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"typing/static",
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"typing/strong",
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"used_for/financial_systems",
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"used_for/scientific_calculations"
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]

‎exercises/practice/sieve/.docs/instructions.md

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# Instructions
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Your task is to create a program that implements the Sieve of Eratosthenes algorithm to find all prime numbers less than or equal to a given number.
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A prime number is a number larger than 1 that is only divisible by 1 and itself.
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For example, 2, 3, 5, 7, 11, and 13 are prime numbers.
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By contrast, 6 is _not_ a prime number as it not only divisible by 1 and itself, but also by 2 and 3.
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To use the Sieve of Eratosthenes, you first create a list of all the numbers between 2 and your given number.
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Then you repeat the following steps:
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1. Find the next unmarked number in your list (skipping over marked numbers).
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This is a prime number.
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2. Mark all the multiples of that prime number as **not** prime.
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You keep repeating these steps until you've gone through every number in your list.
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At the end, all the unmarked numbers are prime.
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~~~~exercism/note
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The tests don't check that you've implemented the algorithm, only that you've come up with the correct list of primes.
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To check you are implementing the Sieve correctly, a good first test is to check that you do not use division or remainder operations.
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~~~~
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## Example
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Let's say you're finding the primes less than or equal to 10.
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- List out 2, 3, 4, 5, 6, 7, 8, 9, 10, leaving them all unmarked.
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- 2 is unmarked and is therefore a prime.
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Mark 4, 6, 8 and 10 as "not prime".
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- 3 is unmarked and is therefore a prime.
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Mark 6 and 9 as not prime _(marking 6 is optional - as it's already been marked)_.
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- 4 is marked as "not prime", so we skip over it.
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- 5 is unmarked and is therefore a prime.
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Mark 10 as not prime _(optional - as it's already been marked)_.
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- 6 is marked as "not prime", so we skip over it.
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- 7 is unmarked and is therefore a prime.
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- 8 is marked as "not prime", so we skip over it.
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- 9 is marked as "not prime", so we skip over it.
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- 10 is marked as "not prime", so we stop as there are no more numbers to check.
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You've examined all numbers and found 2, 3, 5, and 7 are still unmarked, which means they're the primes less than or equal to 10.

‎exercises/practice/sieve/.docs/introduction.md

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# Introduction
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You bought a big box of random computer parts at a garage sale.
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You've started putting the parts together to build custom computers.
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You want to test the performance of different combinations of parts, and decide to create your own benchmarking program to see how your computers compare.
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You choose the famous "Sieve of Eratosthenes" algorithm, an ancient algorithm, but one that should push your computers to the limits.

‎exercises/practice/sieve/.meta/config.json

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{
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"authors": [
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"kahgoh"
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],
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"files": {
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"solution": [
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"sieve.ml"
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],
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"test": [
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"test.ml"
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],
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"example": [
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".meta/example.ml"
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]
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},
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"blurb": "Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number.",
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"source": "Sieve of Eratosthenes at Wikipedia",
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"source_url": "https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes"
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}

‎exercises/practice/sieve/.meta/example.ml

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module IntSet = Set.Make (Int)
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let rec mark (start : int) (step : int) (stop : int) (composites : IntSet.t) =
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match (start, step, stop, composites) with
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| start, _step, stop, composites when start > stop -> composites
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| start, step, stop, composites when IntSet.mem start composites ->
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mark (start + step) step stop composites
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| start, step, stop, composites ->
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mark (start + step) step stop (IntSet.add start composites)
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let rec sift (start : int) (stop : int) (acc : int list) (composites : IntSet.t)
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=
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match (start, stop, acc, composites) with
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| start, stop, acc, _composites when start > stop -> acc
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| start, stop, acc, composites when IntSet.mem start composites ->
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sift (start + 1) stop acc composites
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| start, stop, acc, composites ->
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sift (start + 1) stop (start :: acc)
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(mark (start * 2) start stop composites)
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let primes (limit : int) =
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match limit with
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| limit when limit < 2 -> []
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| limit -> sift 2 limit [] IntSet.empty

‎exercises/practice/sieve/.meta/tests.toml

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# This is an auto-generated file.
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#
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# Regenerating this file via `configlet sync` will:
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# - Recreate every `description` key/value pair
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# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
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# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
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# - Preserve any other key/value pair
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#
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# As user-added comments (using the # character) will be removed when this file
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# is regenerated, comments can be added via a `comment` key.
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[88529125-c4ce-43cc-bb36-1eb4ddd7b44f]
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description = "no primes under two"
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[4afe9474-c705-4477-9923-840e1024cc2b]
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description = "find first prime"
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[974945d8-8cd9-4f00-9463-7d813c7f17b7]
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description = "find primes up to 10"
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[2e2417b7-3f3a-452a-8594-b9af08af6d82]
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description = "limit is prime"
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[92102a05-4c7c-47de-9ed0-b7d5fcd00f21]
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description = "find primes up to 1000"

‎exercises/practice/sieve/Makefile

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default: clean test
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test:
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dune runtest
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clean:
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dune clean
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.PHONY: clean

‎exercises/practice/sieve/dune

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(executable
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(name test)
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(libraries base ounit2))
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(alias
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(name runtest)
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(deps (:x test.exe))
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(action (run %{x})))
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(alias
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(name buildtest)
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(deps (:x test.exe)))
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(env
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(dev
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(flags (:standard -warn-error -A))))

‎exercises/practice/sieve/dune-project

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(lang dune 1.1)
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(version 1.0)

‎exercises/practice/sieve/sieve.ml

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let primes _ =
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failwith "'primes' is missing"

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