refactor: improve PythagoreanTriple logic and add parameterized tests (#6350)

alxkm · web-flow · commit fa2ca9db390e · 2025-07-08T00:29:52.000+03:00
diff --git a/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java b/src/main/java/com/thealgorithms/maths/PythagoreanTriple.java
@@ -1,36 +1,43 @@
 package com.thealgorithms.maths;
 
 /**
- * https://en.wikipedia.org/wiki/Pythagorean_triple
+ * Utility class to check if three integers form a Pythagorean triple.
+ * A Pythagorean triple consists of three positive integers a, b, and c,
+ * such that a² + b² = c².
+ *
+ * Common examples:
+ * - (3, 4, 5)
+ * - (5, 12, 13)
+ *
+ * Reference: https://en.wikipedia.org/wiki/Pythagorean_triple
  */
 public final class PythagoreanTriple {
-    private PythagoreanTriple() {
-    }
 
-    public static void main(String[] args) {
-        assert isPythagTriple(3, 4, 5);
-        assert isPythagTriple(5, 12, 13);
-        assert isPythagTriple(6, 8, 10);
-        assert !isPythagTriple(10, 20, 30);
-        assert !isPythagTriple(6, 8, 100);
-        assert !isPythagTriple(-1, -1, 1);
+    private PythagoreanTriple() {
     }
 
     /**
-     * Check if a,b,c are a Pythagorean Triple
+     * Checks whether three integers form a Pythagorean triple.
+     * The order of parameters does not matter.
      *
-     * @param a x/y component length of a right triangle
-     * @param b y/x component length of a right triangle
-     * @param c hypotenuse length of a right triangle
-     * @return boolean <tt>true</tt> if a, b, c satisfy the Pythagorean theorem,
-     * otherwise
-     * <tt>false</tt>
+     * @param a one side length
+     * @param b another side length
+     * @param c another side length
+     * @return {@code true} if (a, b, c) can form a Pythagorean triple, otherwise {@code false}
      */
     public static boolean isPythagTriple(int a, int b, int c) {
         if (a <= 0 || b <= 0 || c <= 0) {
             return false;
-        } else {
-            return (a * a) + (b * b) == (c * c);
         }
+
+        // Sort the sides so the largest is treated as hypotenuse
+        int[] sides = {a, b, c};
+        java.util.Arrays.sort(sides);
+
+        int x = sides[0];
+        int y = sides[1];
+        int hypotenuse = sides[2];
+
+        return x * x + y * y == hypotenuse * hypotenuse;
     }
 }
diff --git a/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java b/src/test/java/com/thealgorithms/maths/PythagoreanTripleTest.java
@@ -1,22 +1,24 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 
 public class PythagoreanTripleTest {
 
+    @ParameterizedTest
+    @CsvSource({"3, 4, 5, true", "6, 8, 10, true", "9, 12, 15, true", "12, 16, 20, true", "15, 20, 25, true", "18, 24, 30, true", "5, 20, 30, false", "6, 8, 100, false", "-2, -2, 2, false", "0, 0, 0, false", "5, 5, 5, false"})
+    void testIsPythagoreanTriple(int a, int b, int c, boolean expected) {
+        assertEquals(expected, PythagoreanTriple.isPythagTriple(a, b, c));
+    }
+
     @Test
-    public void testPythagoreanTriple() {
-        assertTrue(PythagoreanTriple.isPythagTriple(3, 4, 5));
-        assertTrue(PythagoreanTriple.isPythagTriple(6, 8, 10));
-        assertTrue(PythagoreanTriple.isPythagTriple(9, 12, 15));
-        assertTrue(PythagoreanTriple.isPythagTriple(12, 16, 20));
-        assertTrue(PythagoreanTriple.isPythagTriple(15, 20, 25));
-        assertTrue(PythagoreanTriple.isPythagTriple(18, 24, 30));
-        assertFalse(PythagoreanTriple.isPythagTriple(5, 20, 30));
-        assertFalse(PythagoreanTriple.isPythagTriple(6, 8, 100));
-        assertFalse(PythagoreanTriple.isPythagTriple(-2, -2, 2));
+    void testUnorderedInputStillValid() {
+        // Should still detect Pythagorean triples regardless of argument order
+        assertTrue(PythagoreanTriple.isPythagTriple(5, 3, 4));
+        assertTrue(PythagoreanTriple.isPythagTriple(13, 12, 5));
     }
 }
