feat: Add countLeadingZeros new algorithm with Junit tests

Author: Hardvan

src/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java

@@ -0,0 +1,27 @@
+package com.thealgorithms.bitmanipulation;
+
+public class CountLeadingZeros {
+
+    /**
+     * Counts the number of leading zeros in the binary representation of a number.
+     * Method: Keep shifting the mask to the right until the leftmost bit is 1.
+     * The number of shifts is the number of leading zeros.
+     *
+     * @param num The input number.
+     * @return The number of leading zeros.
+     */
+    public static int countLeadingZeros(int num) {
+        if (num == 0) {
+            return 32;
+        }
+
+        int count = 0;
+        int mask = 1 << 31;
+        while ((mask & num) == 0) {
+            count++;
+            mask >>>= 1;
+        }
+
+        return count;
+    }
+}

src/test/java/com/thealgorithms/bitmanipulation/CountLeadingZerosTest.java

@@ -0,0 +1,16 @@
+package com.thealgorithms.bitmanipulation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class CountLeadingZerosTest {
+
+    @Test
+    public void testCountLeadingZeros() {
+        assertEquals(29, CountLeadingZeros.countLeadingZeros(5));   // 000...0101 has 29 leading zeros
+        assertEquals(32, CountLeadingZeros.countLeadingZeros(0));   // 000...0000 has 32 leading zeros
+        assertEquals(31, CountLeadingZeros.countLeadingZeros(1));   // 000...0001 has 31 leading zeros
+        assertEquals(0, CountLeadingZeros.countLeadingZeros(-1));   // No leading zeros in negative number (-1)
+    }
+}