Add GCD and LCM

src/main/kotlin/com/kylecorry/sol/math/SolMath.kt

@@ -460,4 +460,35 @@ object SolMath {
         }
     }
 
+    fun greatestCommonDivisor(a: Long, b: Long): Long {
+        val maxIterations = 1000
+        var currentA = a
+        var currentB = b
+        var iterations = 0
+        while (currentB != 0L && iterations < maxIterations) {
+            val temp = currentB
+            currentB = currentA % currentB
+            currentA = temp
+            iterations++
+        }
+        return currentA
+    }
+
+    fun greatestCommonDivisor(a: Int, b: Int): Int {
+        return greatestCommonDivisor(a.toLong(), b.toLong()).toInt()
+    }
+
+    fun leastCommonMultiple(a: Long, b: Long): Long {
+        if (a == 0L || b == 0L) {
+            return 0
+        }
+        return abs(a) * (abs(b) / greatestCommonDivisor(a, b))
+    }
+
+    fun leastCommonMultiple(a: Int, b: Int): Int {
+        return leastCommonMultiple(a.toLong(), b.toLong()).toInt()
+    }
+
+
+
 }

src/test/kotlin/com/kylecorry/sol/math/SolMathTest.kt

@@ -436,6 +436,38 @@ class SolMathTest {
         assertEquals(expected, actual)
     }
 
+    @ParameterizedTest
+    @CsvSource(
+        "1, 1, 1",
+        "100, 200, 100",
+        "200, 100, 100",
+        "0, 0, 0",
+        "0, 1, 1",
+        "1, 0, 1",
+        "-1, 1, 1",
+        "400, 600, 200",
+    )
+    fun greatestCommonDivisor(a: Int, b: Int, expected: Int) {
+        val actual = SolMath.greatestCommonDivisor(a, b)
+        assertEquals(expected, actual)
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        "1, 1, 1",
+        "100, 200, 200",
+        "200, 100, 200",
+        "0, 0, 0",
+        "0, 1, 0",
+        "1, 0, 0",
+        "-1, 1, 1",
+        "400, 600, 1200",
+    )
+    fun leastCommonMultiple(a: Int, b: Int, expected: Int) {
+        val actual = SolMath.leastCommonMultiple(a, b)
+        assertEquals(expected, actual)
+    }
+
     companion object {
 
         @JvmStatic