Merge branch 'TheAlgorithms:master' into master

Author: Krounosity

DIRECTORY.md

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+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class provides methods to convert between BCD (Binary-Coded Decimal) and binary.
+ *
+ * Binary-Coded Decimal (BCD) is a class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of binary digits, usually four or eight.
+ *
+ * For more information, refer to the
+ * <a href="https://en.wikipedia.org/wiki/Binary-coded_decimal">Binary-Coded Decimal</a> Wikipedia page.
+ *
+ * <b>Example usage:</b>
+ * <pre>
+ * int binary = BcdConversion.bcdToBinary(0x1234);
+ * System.out.println("BCD 0x1234 to binary: " + binary); // Output: 1234
+ *
+ * int bcd = BcdConversion.binaryToBcd(1234);
+ * System.out.println("Binary 1234 to BCD: " + Integer.toHexString(bcd)); // Output: 0x1234
+ * </pre>
+ */
+public final class BcdConversion {
+    private BcdConversion() {
+    }
+    /**
+     * Converts a BCD (Binary-Coded Decimal) number to binary.
+     *
+     * @param bcd The BCD number.
+     * @return The corresponding binary number.
+     */
+    public static int bcdToBinary(int bcd) {
+        int binary = 0;
+        int multiplier = 1;
+        while (bcd > 0) {
+            int digit = bcd & 0xF; // Extract the last 4 bits (one BCD digit)
+            binary += digit * multiplier;
+            multiplier *= 10;
+            bcd >>= 4; // Shift right by 4 bits to process the next BCD digit
+        }
+        return binary;
+    }
+
+    /**
+     * Converts a binary number to BCD (Binary-Coded Decimal).
+     *
+     * @param binary The binary number.
+     * @return The corresponding BCD number.
+     */
+    public static int binaryToBcd(int binary) {
+        int bcd = 0;
+        int shift = 0;
+        while (binary > 0) {
+            int digit = binary % 10; // Extract the last decimal digit
+            bcd |= (digit << (shift * 4)); // Shift the digit to the correct BCD position
+            binary /= 10; // Remove the last decimal digit
+            shift++;
+        }
+        return bcd;
+    }
+}

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

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+package com.thealgorithms.bitmanipulation;
+
+/**
+ * This class contains a method to check if the binary representation of a number is a palindrome.
+ * <p>
+ *     A binary palindrome is a number whose binary representation is the same when read from left to right and right to left.
+ *     For example, the number 9 has a binary representation of 1001, which is a palindrome.
+ *     The number 10 has a binary representation of 1010, which is not a palindrome.
+ * </p>
+ *
+ * @author Hardvan
+ */
+public final class BinaryPalindromeCheck {
+    private BinaryPalindromeCheck() {
+    }
+
+    /**
+     * Checks if the binary representation of a number is a palindrome.
+     *
+     * @param x The number to check.
+     * @return True if the binary representation is a palindrome, otherwise false.
+     */
+    public static boolean isBinaryPalindrome(int x) {
+        int reversed = reverseBits(x);
+        return x == reversed;
+    }
+
+    /**
+     * Helper function to reverse all the bits of an integer.
+     *
+     * @param x The number to reverse the bits of.
+     * @return The number with reversed bits.
+     */
+    private static int reverseBits(int x) {
+        int result = 0;
+        while (x > 0) {
+            result <<= 1;
+            result |= (x & 1);
+            x >>= 1;
+        }
+        return result;
+    }
+}

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

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+package com.thealgorithms.bitmanipulation;
+
+import java.util.List;
+
+/**
+ * Implements various Boolean algebra gates (AND, OR, NOT, XOR, NAND, NOR)
+ */
+public final class BooleanAlgebraGates {
+
+    private BooleanAlgebraGates() {
+        // Prevent instantiation
+    }
+
+    /**
+     * Represents a Boolean gate that takes multiple inputs and returns a result.
+     */
+    interface BooleanGate {
+        /**
+         * Evaluates the gate with the given inputs.
+         *
+         * @param inputs The input values for the gate.
+         * @return The result of the evaluation.
+         */
+        boolean evaluate(List<Boolean> inputs);
+    }
+
+    /**
+     * AND Gate implementation.
+     * Returns true if all inputs are true; otherwise, false.
+     */
+    static class ANDGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            for (boolean input : inputs) {
+                if (!input) {
+                    return false;
+                }
+            }
+            return true;
+        }
+    }
+
+    /**
+     * OR Gate implementation.
+     * Returns true if at least one input is true; otherwise, false.
+     */
+    static class ORGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            for (boolean input : inputs) {
+                if (input) {
+                    return true;
+                }
+            }
+            return false;
+        }
+    }
+
+    /**
+     * NOT Gate implementation (Unary operation).
+     * Negates a single input value.
+     */
+    static class NOTGate {
+        /**
+         * Evaluates the negation of the input.
+         *
+         * @param input The input value to be negated.
+         * @return The negated value.
+         */
+        public boolean evaluate(boolean input) {
+            return !input;
+        }
+    }
+
+    /**
+     * XOR Gate implementation.
+     * Returns true if an odd number of inputs are true; otherwise, false.
+     */
+    static class XORGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            boolean result = false;
+            for (boolean input : inputs) {
+                result ^= input;
+            }
+            return result;
+        }
+    }
+
+    /**
+     * NAND Gate implementation.
+     * Returns true if at least one input is false; otherwise, false.
+     */
+    static class NANDGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            return !new ANDGate().evaluate(inputs); // Equivalent to negation of AND
+        }
+    }
+
+    /**
+     * NOR Gate implementation.
+     * Returns true if all inputs are false; otherwise, false.
+     */
+    static class NORGate implements BooleanGate {
+        @Override
+        public boolean evaluate(List<Boolean> inputs) {
+            return !new ORGate().evaluate(inputs); // Equivalent to negation of OR
+        }
+    }
+}

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

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+package com.thealgorithms.bitmanipulation;
+
+/**
+ * ClearLeftmostSetBit class contains a method to clear the leftmost set bit of a number.
+ * The leftmost set bit is the leftmost bit that is set to 1 in the binary representation of a number.
+ *
+ * Example:
+ * 26 (11010) -> 10 (01010)
+ * 1 (1) -> 0 (0)
+ * 7 (111) -> 3 (011)
+ * 6 (0110) -> 2 (0010)
+ *
+ * @author Hardvan
+ */
+public final class ClearLeftmostSetBit {
+    private ClearLeftmostSetBit() {
+    }
+
+    /**
+     * Clears the leftmost set bit (1) of a given number.
+     * Step 1: Find the position of the leftmost set bit
+     * Step 2: Create a mask with all bits set except for the leftmost set bit
+     * Step 3: Clear the leftmost set bit using AND with the mask
+     *
+     * @param num The input number.
+     * @return The number after clearing the leftmost set bit.
+     */
+    public static int clearLeftmostSetBit(int num) {
+        int pos = 0;
+        int temp = num;
+        while (temp > 0) {
+            temp >>= 1;
+            pos++;
+        }
+
+        int mask = ~(1 << (pos - 1));
+        return num & mask;
+    }
+}

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

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+package com.thealgorithms.bitmanipulation;
+
+/**
+ * CountLeadingZeros class contains a method to count the number of leading zeros in the binary representation of a number.
+ * The number of leading zeros is the number of zeros before the leftmost 1 bit.
+ * For example, the number 5 has 29 leading zeros in its 32-bit binary representation.
+ * The number 0 has 32 leading zeros.
+ * The number 1 has 31 leading zeros.
+ * The number -1 has no leading zeros.
+ *
+ * @author Hardvan
+ */
+public final class CountLeadingZeros {
+    private 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/main/java/com/thealgorithms/bitmanipulation/CountLeadingZeros.java

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+package com.thealgorithms.bitmanipulation;
+
+/**
+ * A utility class to find the Nth bit of a given number.
+ *
+ * <p>This class provides a method to extract the value of the Nth bit (either 0 or 1)
+ * from the binary representation of a given integer.
+ *
+ * <p>Example:
+ * <pre>{@code
+ * int result = FindNthBit.findNthBit(5, 2); // returns 0 as the 2nd bit of 5 (binary 101) is 0.
+ * }</pre>
+ *
+ * <p>Author: <a href="https://github.com/Tuhinm2002">Tuhinm2002</a>
+ */
+public final class FindNthBit {
+
+    /**
+     * Private constructor to prevent instantiation.
+     *
+     * <p>This is a utility class, and it should not be instantiated.
+     * Attempting to instantiate this class will throw an UnsupportedOperationException.
+     */
+    private FindNthBit() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    /**
+     * Finds the value of the Nth bit of the given number.
+     *
+     * <p>This method uses bitwise operations to extract the Nth bit from the
+     * binary representation of the given integer.
+     *
+     * @param num the integer number whose Nth bit is to be found
+     * @param n   the bit position (1-based) to retrieve
+     * @return    the value of the Nth bit (0 or 1)
+     * @throws IllegalArgumentException if the bit position is less than 1
+     */
+    public static int findNthBit(int num, int n) {
+        if (n < 1) {
+            throw new IllegalArgumentException("Bit position must be greater than or equal to 1.");
+        }
+        // Shifting the number to the right by (n - 1) positions and checking the last bit
+        return (num & (1 << (n - 1))) >> (n - 1);
+    }
+}

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

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+package com.thealgorithms.bitmanipulation;
+
+/**
+ * Gray code is a binary numeral system where two successive values differ in only one bit.
+ * This is a simple conversion between binary and Gray code.
+ * Example:
+ * 7 -> 0111 -> 0100 -> 4
+ * 4 -> 0100 -> 0111 -> 7
+ * 0 -> 0000 -> 0000 -> 0
+ * 1 -> 0001 -> 0000 -> 0
+ * 2 -> 0010 -> 0011 -> 3
+ * 3 -> 0011 -> 0010 -> 2
+ *
+ * @author Hardvan
+ */
+public final class GrayCodeConversion {
+    private GrayCodeConversion() {
+    }
+
+    /**
+     * Converts a binary number to Gray code.
+     *
+     * @param num The binary number.
+     * @return The corresponding Gray code.
+     */
+    public static int binaryToGray(int num) {
+        return num ^ (num >> 1);
+    }
+
+    /**
+     * Converts a Gray code number back to binary.
+     *
+     * @param gray The Gray code number.
+     * @return The corresponding binary number.
+     */
+    public static int grayToBinary(int gray) {
+        int binary = gray;
+        while (gray > 0) {
+            gray >>= 1;
+            binary ^= gray;
+        }
+        return binary;
+    }
+}