Merge pull request #11 from drupol/issue-10-fix-issue-with-factorial

Issue #10: Do not use a formula to compute the count.
drupol · May 29, 2018 · 4dc6c2c · 4dc6c2c
2 parents ff8a6e9 + b7305ab
commit 4dc6c2c
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Showing 2 changed files with 20 additions and 3 deletions.
diff --git a/src/Iterators/Combinations.php b/src/Iterators/Combinations.php
@@ -86,8 +86,13 @@ public function valid()
      */
     public function count()
     {
-        return $this->fact(count($this->getDataset())) /
-          ($this->fact($this->getLength()) * $this->fact(count($this->getDataset()) - $this->getLength()));
+        $i = 0;
+
+        for ($this->rewind(); $this->valid(); $this->next()) {
+            ++$i;
+        }
+
+        return $i;
     }
 
     /**

diff --git a/tests/src/Iterators/CombinationsTest.php b/tests/src/Iterators/CombinationsTest.php
@@ -29,7 +29,8 @@ public function testCombinations($input, $expected)
 
         $this->assertEquals($input['dataset'], $combinations->getDataset());
         $this->assertEquals($input['length'], $combinations->getLength());
-        $this->assertEquals(count($input['dataset']), count($combinations->getDataset()));
+        $this->assertCount(count($input['dataset']),
+            $combinations->getDataset());
         $this->assertEquals(
             $expected['dataset'],
             $combinations->toArray(),
@@ -40,4 +41,15 @@ public function testCombinations($input, $expected)
         );
         $this->assertEquals($expected['count'], $combinations->count());
     }
+
+    /**
+     * Test combinations with big numbers.
+     *
+     * @see https://github.com/drupol/phpermutations/issues/10
+     */
+    public function testCombinationsWithBigNumbers()
+    {
+        $combinations = new Combinations(range(1, 200), 2);
+        $this->assertCount($combinations->count(), $combinations->toArray());
+    }
 }