Initial commit

.editorconfig

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+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 4
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.yaml]
+indent_size = 2

.gitattributes

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+*.bat text eol=crlf

.github/workflows/ci.yaml

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+name: CI
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+            tasks: build
+
+          - os: macos-latest
+            tasks: >
+              iosX64Test
+              macosX64Test
+              tvosX64Test
+              watchosX64Test
+
+          - os: windows-latest
+            tasks: mingwX64Test
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout Project
+        uses: actions/checkout@v4
+
+      - name: Validate Gradle Wrapper
+        uses: gradle/wrapper-validation-action@v2
+
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.konan
+          key: ${{ runner.os }}-${{ hashFiles('**/.lock') }}
+
+      - name: Setup JDK
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 8
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v3
+
+      - name: Build with Gradle Wrapper
+        run: ./gradlew ${{ matrix.tasks }}
+
+  publish:
+    needs: build
+    if: github.ref == 'refs/heads/master' && github.event_name == 'push' && needs.build.result == 'success'
+
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+            tasks: >
+              publishAndroidNativeArm32PublicationToMavenRepository
+              publishAndroidNativeArm64PublicationToMavenRepository
+              publishAndroidNativeX64PublicationToMavenRepository
+              publishAndroidNativeX86PublicationToMavenRepository
+              publishJsPublicationToMavenRepository
+              publishJvmPublicationToMavenRepository
+              publishKotlinMultiplatformPublicationToMavenRepository
+              publishLinuxArm64PublicationToMavenRepository
+              publishLinuxX64PublicationToMavenRepository
+              publishWasmJsPublicationToMavenRepository
+
+          - os: windows-latest
+            tasks: publishMingwX64PublicationToMavenRepository
+
+          - os: macos-latest
+            tasks: >
+              publishIosArm64PublicationToMavenRepository
+              publishIosSimulatorArm64PublicationToMavenRepository
+              publishIosX64PublicationToMavenRepository
+              publishMacosArm64PublicationToMavenRepository
+              publishMacosX64PublicationToMavenRepository
+              publishTvosArm64PublicationToMavenRepository
+              publishTvosSimulatorArm64PublicationToMavenRepository
+              publishTvosX64PublicationToMavenRepository
+              publishWatchosArm32PublicationToMavenRepository
+              publishWatchosArm64PublicationToMavenRepository
+              publishWatchosSimulatorArm64PublicationToMavenRepository
+              publishWatchosX64PublicationToMavenRepository
+
+    runs-on: ${{ matrix.os }}
+
+    env:
+      ORG_GRADLE_PROJECT_ossrhUsername: ${{ secrets.OSSRH_USERNAME }}
+      ORG_GRADLE_PROJECT_ossrhPassword: ${{ secrets.OSSRH_PASSWORD }}
+      ORG_GRADLE_PROJECT_signingKeyId: ${{ secrets.SIGNING_KEY_ID }}
+      ORG_GRADLE_PROJECT_signingKey: ${{ secrets.SIGNING_KEY }}
+      ORG_GRADLE_PROJECT_signingPassword: ${{ secrets.SIGNING_PASSWORD }}
+
+    steps:
+      - name: Checkout Project
+        uses: actions/checkout@v4
+
+      - name: Validate Gradle Wrapper
+        uses: gradle/wrapper-validation-action@v2
+
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.konan
+          key: ${{ runner.os }}-${{ hashFiles('**/.lock') }}
+
+      - name: Setup JDK
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 8
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v3
+
+      - name: Publish with Gradle Wrapper
+        run: ./gradlew ${{ matrix.tasks }}

.gitignore

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+# Hidden files
+.*
+
+# Temporary files
+*~
+
+# Git
+!.git*
+
+# GitHub
+!/.github
+
+# EditorConfig
+!.editorconfig
+
+# IntelliJ Idea
+out/
+*.iml
+*.ipr
+*.iws
+
+# Gradle
+build/
+local.properties
+
+# JVM error logs
+hs_err_pid*.log
+replay_pid*.log

LICENSE

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+Copyright (c) 2024 Michael Bull (https://www.michael-bull.com)
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

README.md

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+# kotlin-itertools
+
+[![Maven Central](https://img.shields.io/maven-central/v/com.michael-bull.kotlin-itertools/kotlin-itertools.svg)](https://search.maven.org/search?q=g:com.michael-bull.kotlin-itertools)
+[![CI](https://github.com/michaelbull/kotlin-itertools/actions/workflows/ci.yaml/badge.svg)](https://github.com/michaelbull/kotlin-itertools/actions/workflows/ci.yaml)
+[![License](https://img.shields.io/github/license/michaelbull/kotlin-itertools.svg)](https://github.com/michaelbull/kotlin-itertools/blob/master/LICENSE)
+
+![badge][badge-android]
+![badge][badge-jvm]
+![badge][badge-js]
+![badge][badge-nodejs]
+![badge][badge-linux]
+![badge][badge-windows]
+![badge][badge-wasm]
+![badge][badge-ios]
+![badge][badge-mac]
+![badge][badge-tvos]
+![badge][badge-watchos]
+![badge][badge-js-ir]
+![badge][badge-android-native]
+![badge][badge-apple-silicon]
+
+Multiplatform combinatoric sequences for Kotlin, inspired by [python-itertools][python-itertools].
+
+Initially built as part of my solutions for [Advent of Code 2023][advent-2023].
+
+## Installation
+
+```groovy
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("com.michael-bull.kotlin-itertools:kotlin-itertools:1.0.0")
+}
+```
+
+## Sequences
+
+### Combinations
+
+```kotlin
+fun <T> List<T>.combinations(length: Int = size): Sequence<List<T>>
+
+fun <T> List<T>.pairCombinations(): Sequence<Pair<T, T>>
+
+fun <T> List<T>.tripleCombinations(): Sequence<Triple<T, T, T>>
+```
+
+Returns a sequence that yields `length`-sized combinations from this list.
+
+The combination tuples are emitted in lexicographic order according to the order of this list.
+
+<details>
+<summary><strong>Examples</strong></summary>
+
+```kotlin
+import com.github.michaelbull.itertools.combinations
+import com.github.michaelbull.itertools.pairCombinations
+import com.github.michaelbull.itertools.tripleCombinations
+
+// [[A, B], [A, C], [A, D], [B, C], [B, D], [C, D]]
+fun example1(): List<List<Char>> {
+    return "ABCD".toList()
+        .combinations(length = 2)
+        .toList()
+}
+
+// [(A, B), (A, D), (A, C), (B, D), (B, C), (D, C)]
+fun example2(): List<Pair<Char, Char>> {
+    return "ABDC".toList()
+        .pairCombinations()
+        .toList()
+}
+
+// [(0, 1, 2), (0, 1, 3), (0, 2, 3), (1, 2, 3)]
+fun example3(): List<Triple<Int, Int, Int>> {
+    return (0..3).toList()
+        .tripleCombinations()
+        .toList()
+}
+```
+</details>
+
+### Permutations
+
+```kotlin
+fun <T> List<T>.permutations(length: Int = size): Sequence<List<T>>
+
+fun <T> List<T>.pairPermutations(): Sequence<Pair<T, T>>
+
+fun <T> List<T>.triplePermutations(): Sequence<Triple<T, T, T>>
+```
+
+Returns a sequence that yields `length`-sized permutations from this list.
+
+The permutation tuples are emitted in lexicographic order according to the order of this list.
+
+<details>
+<summary><strong>Examples</strong></summary>
+
+```kotlin
+import com.github.michaelbull.itertools.permutations
+import com.github.michaelbull.itertools.pairPermutations
+import com.github.michaelbull.itertools.triplePermutations
+
+// [[A, B], [A, C], [A, D], [B, A], [B, C], [B, D], [C, A], [C, B], [C, D], [D, A], [D, B], [D, C]]
+fun example1(): List<List<Char>> {
+    return "ABCD".toList()
+        .permutations(length = 2)
+        .toList()
+}
+
+// [(0, 1), (0, 2), (1, 0), (1, 2), (2, 0), (2, 1)]
+fun example2(): List<Pair<Int, Int>> {
+    return (0..2).toList()
+        .pairPermutations()
+        .toList()
+}
+
+// [(0, 1, 2), (0, 2, 1), (1, 0, 2), (1, 2, 0), (2, 0, 1), (2, 1, 0)]
+fun example3(): List<Triple<Int, Int, Int>> {
+    return (0..2).toList()
+        .triplePermutations()
+        .toList()
+}
+```
+</details>
+
+### Cartesian Product
+
+```kotlin
+fun <A, B> Iterable<A>.product(other: Iterable<B>): Sequence<Pair<A, B>>
+fun <A, B, C> Iterable<A>.product(first: Iterable<B>, second: Iterable<C>): Sequence<Triple<A, B, C>>
+
+fun <A, B> Pair<Iterable<A>, Iterable<B>>.product(): Sequence<Pair<A, B>>
+fun <A, B, C> Triple<Iterable<A>, Iterable<B>, Iterable<C>>.product(): Sequence<Triple<A, B, C>>
+
+fun <T> List<List<T>>.product(): Sequence<List<T>>
+```
+
+Returns a sequence that yields the Cartesian product of the input iterables/lists.
+
+The product tuples are emitted in lexicographic order according to the order of this iterable/list.
+
+<details>
+<summary><strong>Examples</strong></summary>
+
+```kotlin
+import com.github.michaelbull.itertools.product
+
+// [(A, x), (A, y), (B, x), (B, y), (C, x), (C, y), (D, x), (D, y)]
+fun example1(): List<Pair<Char, Char>> {
+    val a = "ABCD".toList()
+    val b = "xy".toList()
+    return a.product(b).toList()
+}
+
+// [(A, C, E), (A, C, F), (A, D, E), (A, D, F), (B, C, E), (B, C, F), (B, D, E), (B, D, F)]
+fun example2(): List<Triple<Char, Char, Char>> {
+    val a = "AB".toList()
+    val b = "CD".toList()
+    val c = "EF".toList()
+
+    return Triple(a, b, c)
+        .product()
+        .toList()
+}
+
+// [[A, x], [A, y], [B, x], [B, y], [C, x], [C, y], [D, x], [D, y]]
+fun example3(): List<List<Char>> {
+    val a = "ABCD".toList()
+    val b = "xy".toList()
+
+    return listOf(a, b)
+        .product()
+        .toList()
+}
+```
+</details>
+
+## Contributing
+
+Bug reports and pull requests are welcome on [GitHub][github].
+
+## License
+
+This project is available under the terms of the ISC license. See the
+[`LICENSE`](LICENSE) file for the copyright information and licensing terms.
+
+[python-itertools]: https://docs.python.org/3/library/itertools.html
+[advent-2023]: https://github.com/michaelbull/advent-2023
+[github]: https://github.com/michaelbull/kotlin-itertools
+
+[badge-android]: http://img.shields.io/badge/-android-6EDB8D.svg?style=flat
+[badge-android-native]: http://img.shields.io/badge/support-[AndroidNative]-6EDB8D.svg?style=flat
+[badge-jvm]: http://img.shields.io/badge/-jvm-DB413D.svg?style=flat
+[badge-js]: http://img.shields.io/badge/-js-F8DB5D.svg?style=flat
+[badge-js-ir]: https://img.shields.io/badge/support-[IR]-AAC4E0.svg?style=flat
+[badge-nodejs]: https://img.shields.io/badge/-nodejs-68a063.svg?style=flat
+[badge-linux]: http://img.shields.io/badge/-linux-2D3F6C.svg?style=flat
+[badge-windows]: http://img.shields.io/badge/-windows-4D76CD.svg?style=flat
+[badge-wasm]: https://img.shields.io/badge/-wasm-624FE8.svg?style=flat
+[badge-apple-silicon]: http://img.shields.io/badge/support-[AppleSilicon]-43BBFF.svg?style=flat
+[badge-ios]: http://img.shields.io/badge/-ios-CDCDCD.svg?style=flat
+[badge-mac]: http://img.shields.io/badge/-macos-111111.svg?style=flat
+[badge-watchos]: http://img.shields.io/badge/-watchos-C0C0C0.svg?style=flat
+[badge-tvos]: http://img.shields.io/badge/-tvos-808080.svg?style=flat