Add BigInteger::gcdMultiple()

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.10.1](https://github.com/brick/math/releases/tag/0.10.1) - 2022-08-02
+
+✨ **New features**
+
+- `BigInteger::gcdMultiple()` returns the GCD of multiple `BigInteger` numbers
+
 ## [0.10.0](https://github.com/brick/math/releases/tag/0.10.0) - 2022-06-18
 
 💥 **Breaking changes**

src/BigInteger.php

@@ -359,6 +359,21 @@ public static function ten() : BigInteger
         return $ten;
     }
 
+    public static function gcdMultiple(BigInteger $a, BigInteger ...$n): BigInteger
+    {
+        $result = $a;
+
+        foreach ($n as $next) {
+            $result = $result->gcd($next);
+
+            if ($result->isEqualTo(1)) {
+                return $result;
+            }
+        }
+
+        return $result;
+    }
+
     /**
      * Returns the sum of this number and the given one.
      *

tests/BigIntegerTest.php

@@ -374,6 +374,46 @@ public function testTen() : void
         self::assertSame(BigInteger::ten(), BigInteger::ten());
     }
 
+    /**
+     * @param string[] $values
+     *
+     * @dataProvider providerGcdMultiple
+     */
+    public function testGcdMultiple(array $values, string $expectedGCD): void
+    {
+        $values = array_map(fn (string $value) => BigInteger::of($value), $values);
+        $actualGCD = BigInteger::gcdMultiple(...$values);
+
+        self::assertSame($expectedGCD, (string) $actualGCD);
+    }
+
+    public function providerGcdMultiple(): Generator
+    {
+        // 1 value
+        foreach (['-1', '0', '1'] as $value) {
+            yield [[$value], $value];
+        }
+
+        // 2 values
+        foreach ($this->providerGcd() as [$a, $b, $gcd]) {
+            yield [[$a, $b], $gcd];
+        }
+
+        // n values
+        yield [['2', '4', '7'], '1'];
+        yield [['2', '4', '8'], '2'];
+        yield [['2', '4', '-7'], '1'];
+        yield [['2', '4', '-8'], '2'];
+        yield [['28', '56', '77777'], '7'];
+        yield [['28', '56', '77778'], '2'];
+        yield [['28', '56', '77782'], '2'];
+        yield [['28', '56', '77783'], '1'];
+        yield [['28', '56', '77784'], '28'];
+        yield [['28', '56', '77784', '4'], '4'];
+        yield [['28', '56', '77784', '14'], '14'];
+        yield [['28', '56', '77784', '14', '4'], '2'];
+    }
+
     /**
      * @dataProvider providerMin
      *