Add Xs3Conversion algorithm (#5743)

src/main/java/com/thealgorithms/bitmanipulation/Xs3Conversion.java

@@ -0,0 +1,58 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides methods to convert between XS-3 (Excess-3) and binary.
+ *
+ * Excess-3, also called XS-3, is a binary-coded decimal (BCD) code in which each decimal digit is represented by its corresponding 4-bit binary value plus 3.
+ *
+ * For more information, refer to the
+ * <a href="https://en.wikipedia.org/wiki/Excess-3">Excess-3</a> Wikipedia page.
+ *
+ * <b>Example usage:</b>
+ * <pre>
+ * int binary = Xs3Conversion.xs3ToBinary(0x4567);
+ * System.out.println("XS-3 0x4567 to binary: " + binary); // Output: 1234
+ *
+ * int xs3 = Xs3Conversion.binaryToXs3(1234);
+ * System.out.println("Binary 1234 to XS-3: " + Integer.toHexString(xs3)); // Output: 0x4567
+ * </pre>
+ */
+public final class Xs3Conversion {
+    private Xs3Conversion() {
+    }
+    /**
+     * Converts an XS-3 (Excess-3) number to binary.
+     *
+     * @param xs3 The XS-3 number.
+     * @return The corresponding binary number.
+     */
+    public static int xs3ToBinary(int xs3) {
+        int binary = 0;
+        int multiplier = 1;
+        while (xs3 > 0) {
+            int digit = (xs3 & 0xF) - 3; // Extract the last 4 bits (one XS-3 digit) and subtract 3
+            binary += digit * multiplier;
+            multiplier *= 10;
+            xs3 >>= 4; // Shift right by 4 bits to process the next XS-3 digit
+        }
+        return binary;
+    }
+
+    /**
+     * Converts a binary number to XS-3 (Excess-3).
+     *
+     * @param binary The binary number.
+     * @return The corresponding XS-3 number.
+     */
+    public static int binaryToXs3(int binary) {
+        int xs3 = 0;
+        int shift = 0;
+        while (binary > 0) {
+            int digit = (binary % 10) + 3; // Extract the last decimal digit and add 3
+            xs3 |= (digit << (shift * 4)); // Shift the digit to the correct XS-3 position
+            binary /= 10; // Remove the last decimal digit
+            shift++;
+        }
+        return xs3;
+    }
+}