Add another method to check Pronic number (#5919)

Author: TaranjeetSinghKalsi

src/main/java/com/thealgorithms/maths/PronicNumber.java

@@ -21,6 +21,9 @@ private PronicNumber() {
      * @return true if input number is a pronic number, false otherwise
      */
     static boolean isPronic(int inputNumber) {
+        if (inputNumber == 0) {
+            return true;
+        }
         // Iterating from 0 to input_number
         for (int i = 0; i <= inputNumber; i++) {
             // Checking if product of i and (i+1) is equals input_number
@@ -34,4 +37,15 @@ static boolean isPronic(int inputNumber) {
         // equals input_number
         return false;
     }
+
+    /**
+     * This method checks if the given number is pronic number or non-pronic number using square root of number for finding divisors
+     *
+     * @param number Integer value which is to be checked if is a pronic number or not
+     * @return true if input number is a pronic number, false otherwise
+     */
+    public static boolean isPronicNumber(int number) {
+        int squareRoot = (int) Math.sqrt(number); // finding just smaller divisor of the number than its square root.
+        return squareRoot * (squareRoot + 1) == number;
+    }
 }

src/test/java/com/thealgorithms/maths/PronicNumberTest.java

@@ -1,33 +1,22 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 public class PronicNumberTest {
 
-    @Test
-    void testForPronicNumber() {
-        // given
-        int number = 30;
-
-        // when
-        boolean result = PronicNumber.isPronic(number);
-
-        // then
-        assertTrue(result);
+    @ParameterizedTest
+    @ValueSource(ints = {0, 2, 6, 12, 20, 30, 42, 110, 272, 380, 420, 1260, 2550})
+    void testForPronicNumber(final int number) {
+        Assertions.assertTrue(PronicNumber.isPronic(number));
+        Assertions.assertTrue(PronicNumber.isPronicNumber(number));
     }
 
-    @Test
-    void testForNonPronicNumber() {
-        // given
-        int number = 21;
-
-        // when
-        boolean result = PronicNumber.isPronic(number);
-
-        // then
-        assertFalse(result);
+    @ParameterizedTest
+    @ValueSource(ints = {1, 4, 21, 36, 150, 2500})
+    void testForNonPronicNumber(final int number) {
+        Assertions.assertFalse(PronicNumber.isPronic(number));
+        Assertions.assertFalse(PronicNumber.isPronicNumber(number));
     }
 }