Initial commit.

.scrutinizer.yml

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+build:
+    environment:
+        php: '5.6'
+
+filter:
+    paths:
+        - 'src/*'
+
+tools:
+    external_code_coverage:
+        timeout: 600
+    php_mess_detector:
+        config:
+            code_size_rules: { cyclomatic_complexity: true, npath_complexity: true, excessive_method_length: true, excessive_class_length: true, excessive_parameter_list: true, excessive_public_count: true, too_many_fields: true, too_many_methods: true, excessive_class_complexity: true }
+            design_rules: { number_of_class_children: true, depth_of_inheritance: true, coupling_between_objects: true }
+            unused_code_rules: { unused_local_variable: true, unused_private_method: true, unused_formal_parameter: true }
+            naming_rules: { short_variable: true, long_variable: true, short_method: true, boolean_method_name: true }
+            controversial_rules: { camel_case_class_name: true, camel_case_property_name: true, camel_case_method_name: true, camel_case_parameter_name: true, camel_case_variable_name: true }
+    php_cs_fixer:
+        config:
+            level: all
+            fixers: { unused_use: true, phpdoc_params: true, braces: true, php_closing_tag: true }
+    php_analyzer:
+        config:
+            suspicious_code: { enabled: true, overriding_parameter: true, overriding_closure_use: true, parameter_closure_use_conflict: true, parameter_multiple_times: true, non_existent_class_in_instanceof_check: true, non_existent_class_in_catch_clause: true, assignment_of_null_return: true, non_commented_switch_fallthrough: true, non_commented_empty_catch_block: true, overriding_private_members: true, use_statement_alias_conflict: true, precedence_in_condition_assignment: true }
+            verify_php_doc_comments: { enabled: true, parameters: true, return: true, suggest_more_specific_types: true, ask_for_return_if_not_inferrable: true, ask_for_param_type_annotation: true }
+            loops_must_use_braces: { enabled: true }
+            simplify_boolean_return: { enabled: true }
+            phpunit_checks: { enabled: true }
+            reflection_fixes: { enabled: true }
+            use_statement_fixes: { enabled: true, order_alphabetically: true, remove_unused: true, preserve_multiple: false, preserve_blanklines: false }
+            parameter_reference_check: { enabled: false }
+            checkstyle: { enabled: false, no_trailing_whitespace: true, naming: { enabled: true, local_variable: '^[a-z][a-zA-Z0-9]*$', abstract_class_name: ^Abstract|Factory$, utility_class_name: 'Utils?$', constant_name: '^[A-Z][A-Z0-9]*(?:_[A-Z0-9]+)*$', property_name: '^[a-z][a-zA-Z0-9]*$', method_name: '^(?:[a-z]|__)[a-zA-Z0-9]*$', parameter_name: '^[a-z][a-zA-Z0-9]*$', interface_name: '^[A-Z][a-zA-Z0-9]*Interface$', type_name: '^[A-Z][a-zA-Z0-9]*$', exception_name: '^[A-Z][a-zA-Z0-9]*Exception$', isser_method_name: '^(?:is|has|should|may|supports)' } }
+            unreachable_code: { enabled: false }
+            check_access_control: { enabled: false }
+            typo_checks: { enabled: false }
+            check_variables: { enabled: false }
+            check_calls: { enabled: true, too_many_arguments: true, missing_argument: true, argument_type_checks: lenient }
+            dead_assignments: { enabled: false }
+            check_usage_context: { enabled: true, foreach: { value_as_reference: true, traversable: true } }
+            reflection_checks: { enabled: false }
+            precedence_checks: { enabled: true, assignment_in_condition: true, comparison_of_bit_result: true }
+            basic_semantic_checks: { enabled: false }
+            unused_code: { enabled: false }
+            deprecation_checks: { enabled: false }
+            useless_function_calls: { enabled: false }
+            metrics_lack_of_cohesion_methods: { enabled: false }
+            metrics_coupling: { enabled: true, stable_code: { namespace_prefixes: {  }, classes: {  } } }
+            doctrine_parameter_binding: { enabled: false }
+            doctrine_entity_manager_injection: { enabled: false }
+            symfony_request_injection: { enabled: false }
+            doc_comment_fixes: { enabled: false }
+    php_code_sniffer:
+        config:
+            standard: PSR2
+            sniffs: { psr2: { classes: { property_declaration_sniff: true }, methods: { method_declaration_sniff: true } } }
+    sensiolabs_security_checker: true
+    php_loc: true
+    php_pdepend: true
+    php_sim: true
+    php_changetracking: true

.travis.yml

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+language: php
+
+git:
+  depth: 1
+
+cache:
+  directories:
+    - $HOME/.cache/composer
+    - $HOME/.composer/cache
+
+php:
+  - 5.6
+  - 7.1
+
+install:
+  - composer install
+
+script:
+  - composer phpunit
+
+after_success:
+  - composer scrutinizer

README.md

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+## PHPartition
+[![Build Status](https://travis-ci.org/drupol/phpartition.svg?branch=master)](https://travis-ci.org/drupol/phpartition) [![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/drupol/phpartition/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/drupol/phpartition/?branch=master) [![Dependency Status](https://www.versioneye.com/user/projects/58551f4d4d6466004c28cc8f/badge.svg?style=flat-square)](https://www.versioneye.com/user/projects/58551f4d4d6466004c28cc8f)
+
+In number theory and computer science, the partition problem is the task of deciding whether a given multiset S of items can be partitioned into multiple balanced subsets.
+
+## Requirements
+
+* PHP >= 5.6,
+* (optional) [PHPUnit](https://phpunit.de/) to run tests.
+
+## Example
+
+```php
+<?php
+
+include "./vendor/autoload.php";
+
+$data = array(1, 5, 5, 11, 6, 7, 9, 3);
+$size = 3;
+
+$greedy = new \drupol\phpartition\Algorithm\Greedy();
+$greedy->setData($data);
+$greedy->setPartition($size);
+$result = $greedy->getResult();
+
+// $result is:
+/*
+ * Array
+   (
+       [0] => Array
+           (
+               [0] => 9
+               [1] => 5
+               [2] => 1
+           )
+
+       [1] => Array
+           (
+               [0] => 7
+               [1] => 6
+               [2] => 3
+           )
+
+       [2] => Array
+           (
+               [0] => 11
+               [1] => 5
+           )
+   )
+ */
+
+
+$simple = new \drupol\phpartition\Algorithm\Simple();
+$simple->setData($data);
+$simple->setPartition($size);
+$result = $simple->getResult();
+
+// $result is:
+/*
+ * Array
+(
+    [0] => Array
+        (
+            [0] => 5
+            [1] => 11
+        )
+
+    [1] => Array
+        (
+            [0] => 1
+            [1] => 7
+            [2] => 3
+        )
+
+    [2] => Array
+        (
+            [0] => 5
+            [1] => 6
+            [2] => 9
+        )
+)
+ */
+```
+You may also pass objects or array but then, you'll have to define how to access their value.
+
+```php
+<?php
+
+include "./vendor/autoload.php";
+
+$data = array(
+  array(
+    'item' => 'anything A',
+    'weight' => 1,
+  ),
+  array(
+    'item' => 'anything B',
+    'weight' => 2,
+  ),
+  array(
+    'item' => 'anything C',
+    'weight' => 3,
+  ),
+  array(
+    'item' => 'anything D',
+    'weight' => 4,
+  ),
+);
+$size = 2;
+
+$greedy = new \drupol\phpartition\Algorithm\Greedy();
+$greedy->setData($data);
+$greedy->setPartition($size);
+$greedy->setItemAccessCallback(function($item) {
+  return $item['weight'];
+});
+$result = $greedy->getResult();
+
+// $result is
+/*
+ * Array
+   (
+       [0] => Array
+           (
+               [0] => Array
+                   (
+                       [item] => anything C
+                       [weight] => 3
+                   )
+
+               [1] => Array
+                   (
+                       [item] => anything B
+                       [weight] => 2
+                   )
+
+           )
+
+       [1] => Array
+           (
+               [0] => Array
+                   (
+                       [item] => anything D
+                       [weight] => 4
+                   )
+
+               [1] => Array
+                   (
+                       [item] => anything A
+                       [weight] => 1
+                   )
+
+           )
+
+   )
+ */
+```
+
+## TODO
+
+- Implement Complete Karmarkar-Karp (CKK) algorithm,
+- Tests,
+- Documentation,
+- Tests coverage.
+

composer.json

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+{
+    "name": "drupol/phpartition",
+    "description": "Partition problem for balanced arrays splitting made easy.",
+    "type": "library",
+    "homepage": "https://github.com/drupol/phpartition",
+    "keywords": ["math", "numbers", "statistics", "partition", "greedy", "karmarkar", "karp"],
+    "license": "GPL-2.0+",
+    "support": {
+        "issues": "https://github.com/drupol/phpartition/issues",
+        "source": "https://github.com/drupol/phpartition"
+    },
+    "authors": [
+        {
+            "name": "Pol Dellaiera",
+            "email": "pol.dellaiera@protonmail.com"
+        }
+    ],
+    "require-dev": {
+        "phpunit/phpunit": "^5.6",
+        "mockery/mockery": "^0.9",
+        "squizlabs/php_codesniffer": "^2.0",
+        "satooshi/php-coveralls": "^1.0",
+        "phpunit/php-code-coverage": "^4.0",
+        "codacy/coverage": "dev-master",
+        "scrutinizer/ocular": "^1.3"
+    },
+    "scripts": {
+        "phpcs": "./vendor/bin/phpcs --ignore=vendor .",
+        "phpcbf": "./vendor/bin/phpcbf --ignore=vendor .",
+        "phpunit": "./vendor/bin/phpunit --coverage-clover build/logs/clover.xml -c tests/phpunit.xml tests",
+        "codacy": "./vendor/bin/codacycoverage clover build/logs/clover.xml",
+        "coveralls": "./vendor/bin/coveralls",
+        "scrutinizer": "./vendor/bin/ocular code-coverage:upload --format=php-clover build/logs/clover.xml"
+    },
+    "autoload": {
+        "psr-4": {
+            "drupol\\phpartition\\": "src/",
+            "drupol\\phpartition\\Tests\\": "tests/src/"
+        }
+    },
+    "require": {
+        "alphazygma/combinatorics": "^1.0",
+        "oefenweb/statistics": "^1.1"
+    }
+}

src/Algorithm/BruteForce.php

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+<?php
+
+namespace drupol\phpartition\Algorithm;
+
+use drupol\phpartition\BasePartitionAlgorithm;
+use drupol\phpartition\PartitionAlgorithmInterface;
+use drupol\phpartition\Subset;
+use Math\Combinatorics\Permutation;
+
+/**
+ * Class BruteForce.
+ *
+ * @package drupol\phpartition\Algorithm
+ */
+class BruteForce extends BasePartitionAlgorithm implements PartitionAlgorithmInterface {
+
+  /**
+   * @return array
+   */
+  public function getResult() {
+    $permutation = new Permutation();
+    $this->dataset->sortByValue('ASC');
+
+    $partitionSize = ($this->getPartition() > $this->dataset->count()) ? $this->dataset->count() : $this->getPartition();
+
+    for ($p=$partitionSize; $p > 1; $p--) {
+      $best = $this->dataset->getWeight();
+      $target = ($best)/ $p;
+      $goodSubset = array();
+      $maxSize = floor($this->dataset->count() / $p);
+
+      for ($i = 1; $i <= $maxSize; $i++) {
+        foreach ($permutation->getPermutations($this->dataset->getItems(), $i) as $subset) {
+          $x = 0;
+          foreach ($subset as $item) {
+            $x += $item->getValue();
+            if (abs($x - $target) - abs($best - $target) < 0) {
+              $best = $x;
+              $goodSubset = $subset;
+            }
+          }
+        }
+      }
+
+      $subset = new Subset();
+      $subset->setAlgo($this);
+      $subset->addItems($goodSubset);
+      $this->getSubsetContainer()->insert($subset);
+      $this->dataset->deleteItems($goodSubset);
+    }
+
+    $subset = new Subset();
+    $subset->setAlgo($this);
+    $subset->addItems($this->dataset->getItems());
+    $this->getSubsetContainer()->insert($subset);
+
+    return $this->getSubsetContainer()->getSubsetsAndItemsAsArray();
+  }
+
+  /**
+   * @param \drupol\phpartition\Subset $subset
+   *
+   * @return int|mixed
+   */
+  public function getSubsetWeight(Subset $subset) {
+    $sum = 0;
+
+    foreach ($subset->getItems() as $item) {
+      $sum += $item->getValue();
+    }
+
+    return $sum;
+  }
+
+}