feat: Digit Separation Algorithm added (TheAlgorithms#2759)

* Digit Separation Algorithm added

* feat: Added namespace greedy_algoriithms

* "Updated digit separation code: added comments and docstrings, changed data types to std::int64_t, and reformatted code."

* feat: Made test function and removed extra whitespaces

* removed some more whitespaces

* Update greedy_algorithms/digit_separation.cpp

Co-authored-by: realstealthninja <[email protected]>

* fix: terminate multiline comment

* Update greedy_algorithms/digit_separation.cpp

Co-authored-by: realstealthninja <[email protected]>

* Update greedy_algorithms/digit_separation.cpp

Co-authored-by: realstealthninja <[email protected]>

* Update greedy_algorithms/digit_separation.cpp

Co-authored-by: realstealthninja <[email protected]>

* Update greedy_algorithms/digit_separation.cpp

Co-authored-by: realstealthninja <[email protected]>

* Corrected test function

* Update greedy_algorithms/digit_separation.cpp

Co-authored-by: realstealthninja <[email protected]>

* Update greedy_algorithms/digit_separation.cpp

Co-authored-by: realstealthninja <[email protected]>

* remove redundant declaration

Co-authored-by: realstealthninja <[email protected]>

* Corrected tests

Co-authored-by: realstealthninja <[email protected]>

* file clang linted

* "Moved method implementations from outside to inside class definition"

* fowardOrder to forwardOrder on line 122

Co-authored-by: realstealthninja <[email protected]>

* Removed Class scope resolution form digitSeparationReverseOrder function

Co-authored-by: realstealthninja <[email protected]>

* Removed Class scope resolution form digitSeparationForwardOrderfunction

Co-authored-by: realstealthninja <[email protected]>

* docs: documentation updated

---------

Co-authored-by: realstealthninja <[email protected]>

Author: mjk22071998

greedy_algorithms/digit_separation.cpp

@@ -0,0 +1,142 @@
+/**
+ * @file digit_separation.cpp
+ * @brief Separates digits from numbers in forward and reverse order
+ * @see https://www.log2base2.com/c-examples/loop/split-a-number-into-digits-in-c.html
+ * @details The DigitSeparation class provides two methods to separate the
+ * digits of large integers: digitSeparationReverseOrder and
+ * digitSeparationForwardOrder. The digitSeparationReverseOrder method extracts
+ * digits by repeatedly applying the modulus operation (% 10) to isolate the
+ * last digit, then divides the number by 10 to remove it. This process
+ * continues until the entire number is broken down into its digits, which are
+ * stored in reverse order. If the number is zero, the method directly returns a
+ * vector containing {0} to handle this edge case. Negative numbers are handled
+ * by taking the absolute value, ensuring consistent behavior regardless of the
+ * sign.
+ * @author [Muhammad Junaid Khalid](https://github.com/mjk22071998)
+ */
+
+#include <algorithm>  /// For reveresing the vector
+#include <cassert>    /// For assert() function to check for errors
+#include <cmath>      /// For abs() function
+#include <cstdint>    /// For int64_t data type to handle large numbers
+#include <iostream>   /// For input/output operations
+#include <vector>     /// For std::vector to store separated digits
+
+/**
+ * @namespace
+ * @brief Greedy Algorithms
+ */
+namespace greedy_algorithms {
+
+/**
+ * @brief A class that provides methods to separate the digits of a large
+ * positive number.
+ */
+class DigitSeparation {
+ public:
+    /**
+     * @brief Default constructor for the DigitSeparation class.
+     */
+    DigitSeparation() {}
+
+    /**
+     * @brief Implementation of digitSeparationReverseOrder method.
+     *
+     * @param largeNumber The large number to separate digits from.
+     * @return A vector of digits in reverse order.
+     */
+    std::vector<std::int64_t> digitSeparationReverseOrder(
+        std::int64_t largeNumber) const {
+        std::vector<std::int64_t> result;
+        if (largeNumber != 0) {
+            while (largeNumber != 0) {
+                result.push_back(std::abs(largeNumber % 10));
+                largeNumber /= 10;
+            }
+        } else {
+            result.push_back(0);
+        }
+        return result;
+    }
+
+    /**
+     * @brief Implementation of digitSeparationForwardOrder method.
+     *
+     * @param largeNumber The large number to separate digits from.
+     * @return A vector of digits in forward order.
+     */
+    std::vector<std::int64_t> digitSeparationForwardOrder(
+        std::int64_t largeNumber) const {
+        std::vector<std::int64_t> result =
+            digitSeparationReverseOrder(largeNumber);
+        std::reverse(result.begin(), result.end());
+        return result;
+    }
+};
+
+}  // namespace greedy_algorithms
+
+/**
+ * @brief self test implementation
+ * @return void
+ */
+static void tests() {
+    greedy_algorithms::DigitSeparation ds;
+
+    // Test case: Positive number
+    std::int64_t number = 1234567890;
+    std::vector<std::int64_t> expectedReverse = {0, 9, 8, 7, 6, 5, 4, 3, 2, 1};
+    std::vector<std::int64_t> expectedForward = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0};
+    std::vector<std::int64_t> reverseOrder =
+        ds.digitSeparationReverseOrder(number);
+    assert(reverseOrder == expectedReverse);
+    std::vector<std::int64_t> forwardOrder =
+        ds.digitSeparationForwardOrder(number);
+    assert(forwardOrder == expectedForward);
+
+    // Test case: Single digit number
+    number = 5;
+    expectedReverse = {5};
+    expectedForward = {5};
+    reverseOrder = ds.digitSeparationReverseOrder(number);
+    assert(reverseOrder == expectedReverse);
+    forwardOrder = ds.digitSeparationForwardOrder(number);
+    assert(forwardOrder == expectedForward);
+
+    // Test case: Zero
+    number = 0;
+    expectedReverse = {0};
+    expectedForward = {0};
+    reverseOrder = ds.digitSeparationReverseOrder(number);
+    assert(reverseOrder == expectedReverse);
+    forwardOrder = ds.digitSeparationForwardOrder(number);
+    assert(forwardOrder == expectedForward);
+
+    // Test case: Large number
+    number = 987654321012345;
+    expectedReverse = {5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+    expectedForward = {9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5};
+    reverseOrder = ds.digitSeparationReverseOrder(number);
+    assert(reverseOrder == expectedReverse);
+    forwardOrder = ds.digitSeparationForwardOrder(number);
+    assert(forwardOrder == expectedForward);
+
+    // Test case: Negative number
+    number = -987654321012345;
+    expectedReverse = {5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+    expectedForward = {9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5};
+    reverseOrder = ds.digitSeparationReverseOrder(number);
+    assert(reverseOrder == expectedReverse);
+    forwardOrder = ds.digitSeparationForwardOrder(number);
+    assert(forwardOrder == expectedForward);
+}
+
+/**
+ * @brief main function
+ * @return 0 on successful exit
+ */
+int main() {
+    tests();  // run self test implementation
+
+    return 0;
+}