Merge branch 'master' into dev/ps_ISSUE-2719

DIRECTORY.md

@@ -19,6 +19,7 @@
   * [Count Of Set Bits](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/bit_manipulation/count_of_set_bits.cpp)
   * [Count Of Trailing Ciphers In Factorial N](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/bit_manipulation/count_of_trailing_ciphers_in_factorial_n.cpp)
   * [Find Non Repeating Number](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/bit_manipulation/find_non_repeating_number.cpp)
+  * [Gray Code](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/bit_manipulation/gray_code.cpp)
   * [Hamming Distance](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/bit_manipulation/hamming_distance.cpp)
   * [Next Higher Number With Same Number Of Set Bits](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/bit_manipulation/next_higher_number_with_same_number_of_set_bits.cpp)
   * [Power Of 2](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/bit_manipulation/power_of_2.cpp)
@@ -161,6 +162,7 @@
 ## Greedy Algorithms
   * [Boruvkas Minimum Spanning Tree](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/greedy_algorithms/boruvkas_minimum_spanning_tree.cpp)
   * [Dijkstra](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/greedy_algorithms/dijkstra.cpp)
+  * [Gale Shapley](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/greedy_algorithms/gale_shapley.cpp)
   * [Huffman](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/greedy_algorithms/huffman.cpp)
   * [Jump Game](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/greedy_algorithms/jump_game.cpp)
   * [Knapsack](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/greedy_algorithms/knapsack.cpp)
@@ -377,6 +379,7 @@
   * [Pigeonhole Sort](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/sorting/pigeonhole_sort.cpp)
   * [Quick Sort](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/sorting/quick_sort.cpp)
   * [Quick Sort 3](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/sorting/quick_sort_3.cpp)
+  * [Quick Sort Iterative](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/sorting/quick_sort_iterative.cpp)
   * [Radix Sort](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/sorting/radix_sort.cpp)
   * [Radix Sort2](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/sorting/radix_sort2.cpp)
   * [Random Pivot Quick Sort](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/sorting/random_pivot_quick_sort.cpp)

bit_manipulation/gray_code.cpp

@@ -0,0 +1,113 @@
+/**
+ * @brief Program to generate n-bit [Gray 
+ * code](https://en.wikipedia.org/wiki/Gray_code)
+ * 
+ * @details
+ * Gray code is a binary numeral system
+ * where consecutive values differ in exactly 1 bit.
+ * The following code offers one of many possible Gray codes 
+ * given some pre-determined number of bits.
+ */
+
+#include <bitset>  /// for gray code representation
+#include <cassert>  /// for assert
+#include <iostream>  /// for IO operations
+#include <vector>  /// for vector data structure
+
+/**
+ * @namespace bit_manipulation
+ * @brief Bit manipulation algorithms
+ */
+namespace bit_manipulation {
+/**
+ * @namespace gray_code
+ * @brief Generate n-bit Gray code
+ */
+namespace gray_code {
+/**
+ * @brief The main function to generate n-bit Gray code
+ *
+ * @param n Number of bits
+ * @return A vector that stores the n-bit Gray code
+ */
+std::vector<std::bitset<32>> gray_code_generation(int n) {
+    std::vector<std::bitset<32>> gray_code = {};  // Initialise empty vector
+
+    // No Gray codes for non-positive values of n
+    if (n <= 0) {
+        return gray_code;
+    }
+
+    int total_codes = 1 << n;  // Number of n-bit gray codes
+
+    for (int i = 0; i < total_codes; i++) {
+        int gray_num = i ^ (i >> 1);  // Gray code formula
+        gray_code.push_back(std::bitset<32>(gray_num));  // Store the value
+    }
+
+    return gray_code;
+} 
+}  // namespace gray_code
+}  // namespace bit_manipulation
+
+/**
+ * @brief Self-test implementation
+ *
+ * @returns void
+ */
+static void test() { 
+    std::vector<std::bitset<32>> gray_code_negative_1 = {};
+
+    std::vector<std::bitset<32>> gray_code_0 = {};
+
+    std::vector<std::bitset<32>> gray_code_1 = {
+        std::bitset<32>(0), std::bitset<32>(1)
+    };
+
+    std::vector<std::bitset<32>> gray_code_2 = {
+        std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2)
+    };
+
+    std::vector<std::bitset<32>> gray_code_3 = {
+        std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2),
+        std::bitset<32>(6), std::bitset<32>(7), std::bitset<32>(5), std::bitset<32>(4)
+    };
+
+    std::vector<std::bitset<32>> gray_code_4 = {
+        std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2),
+        std::bitset<32>(6), std::bitset<32>(7), std::bitset<32>(5), std::bitset<32>(4),
+        std::bitset<32>(12), std::bitset<32>(13), std::bitset<32>(15), std::bitset<32>(14),
+        std::bitset<32>(10), std::bitset<32>(11), std::bitset<32>(9), std::bitset<32>(8)
+    };
+
+    std::vector<std::bitset<32>> gray_code_5 = {
+        std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2),
+        std::bitset<32>(6), std::bitset<32>(7), std::bitset<32>(5), std::bitset<32>(4),
+        std::bitset<32>(12), std::bitset<32>(13), std::bitset<32>(15), std::bitset<32>(14),
+        std::bitset<32>(10), std::bitset<32>(11), std::bitset<32>(9), std::bitset<32>(8),
+        std::bitset<32>(24), std::bitset<32>(25), std::bitset<32>(27), std::bitset<32>(26),
+        std::bitset<32>(30), std::bitset<32>(31), std::bitset<32>(29), std::bitset<32>(28),
+        std::bitset<32>(20), std::bitset<32>(21), std::bitset<32>(23), std::bitset<32>(22),
+        std::bitset<32>(18), std::bitset<32>(19), std::bitset<32>(17), std::bitset<32>(16)
+    };
+
+    // invalid values for n
+    assert(bit_manipulation::gray_code::gray_code_generation(-1) == gray_code_negative_1);
+    assert(bit_manipulation::gray_code::gray_code_generation(0) == gray_code_0);
+
+    // valid values for n
+    assert(bit_manipulation::gray_code::gray_code_generation(1) == gray_code_1);
+    assert(bit_manipulation::gray_code::gray_code_generation(2) == gray_code_2);
+    assert(bit_manipulation::gray_code::gray_code_generation(3) == gray_code_3);
+    assert(bit_manipulation::gray_code::gray_code_generation(4) == gray_code_4);
+    assert(bit_manipulation::gray_code::gray_code_generation(5) == gray_code_5);
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    test();  //Run self-test implementation
+    return 0;
+}

greedy_algorithms/gale_shapley.cpp

@@ -0,0 +1,129 @@
+/**
+ * @file
+ * @brief [Gale Shapley Algorithm](https://en.wikipedia.org/wiki/Gale%E2%80%93Shapley_algorithm)
+ * @details
+ * This implementation utilizes the Gale-Shapley algorithm to find stable matches.
+ *
+ * **Gale Shapley Algorithm** aims to find a stable matching between two equally sized 
+ * sets of elements given an ordinal preference for each element. The algorithm was
+ * introduced by David Gale and Lloyd Shapley in 1962.
+ * 
+ * Reference: 
+ * [Wikipedia](https://en.wikipedia.org/wiki/Gale%E2%80%93Shapley_algorithm)
+ * [Wikipedia](https://en.wikipedia.org/wiki/Stable_matching_problem)
+ *
+ * @author [B Karthik](https://github.com/BKarthik7)
+ */
+
+#include <iostream>   /// for std::u32int_t
+#include <vector>     /// for std::vector
+#include <algorithm>  /// for std::find
+#include <cassert>    /// for assert
+
+/**
+ * @namespace
+ * @brief Greedy Algorithms
+ */
+namespace greedy_algorithms {
+/**
+ * @namespace
+ * @brief Functions for the Gale-Shapley Algorithm
+ */
+namespace stable_matching {
+/**
+ * @brief The main function that finds the stable matching between two sets of elements 
+ * using the Gale-Shapley Algorithm.
+ * @note This doesn't work on negative preferences. the preferences should be continuous integers starting from 
+ * 0 to number of preferences - 1.
+ * @param primary_preferences the preferences of the primary set should be a 2D vector
+ * @param secondary_preferences the preferences of the secondary set should be a 2D vector
+ * @returns matches the stable matching between the two sets
+ */
+std::vector<std::uint32_t> gale_shapley(const std::vector<std::vector<std::uint32_t>>& secondary_preferences, const std::vector<std::vector<std::uint32_t>>& primary_preferences) {
+    std::uint32_t num_elements = secondary_preferences.size();
+    std::vector<std::uint32_t> matches(num_elements, -1);
+    std::vector<bool> is_free_primary(num_elements, true);
+    std::vector<std::uint32_t> proposal_index(num_elements, 0); // Tracks the next secondary to propose for each primary
+
+    while (true) {
+        int free_primary_index = -1;
+
+        // Find the next free primary
+        for (std::uint32_t i = 0; i < num_elements; i++) {
+            if (is_free_primary[i]) {
+                free_primary_index = i;
+                break;
+            }
+        }
+
+        // If no free primary is found, break the loop
+        if (free_primary_index == -1) break;
+
+        // Get the next secondary to propose
+        std::uint32_t secondary_to_propose = primary_preferences[free_primary_index][proposal_index[free_primary_index]];
+        proposal_index[free_primary_index]++;
+
+        // Get the current match of the secondary
+        std::uint32_t current_match = matches[secondary_to_propose];
+
+        // If the secondary is free, match them
+        if (current_match == -1) {
+            matches[secondary_to_propose] = free_primary_index;
+            is_free_primary[free_primary_index] = false;
+        } else {
+            // Determine if the current match should be replaced
+            auto new_proposer_rank = std::find(secondary_preferences[secondary_to_propose].begin(),
+                                                secondary_preferences[secondary_to_propose].end(),
+                                                free_primary_index);
+            auto current_match_rank = std::find(secondary_preferences[secondary_to_propose].begin(),
+                                                 secondary_preferences[secondary_to_propose].end(),
+                                                 current_match);
+
+            // If the new proposer is preferred over the current match
+            if (new_proposer_rank < current_match_rank) {
+                matches[secondary_to_propose] = free_primary_index;
+                is_free_primary[free_primary_index] = false;
+                is_free_primary[current_match] = true; // Current match is now free
+            }
+        }
+    }
+
+    return matches;
+}
+}  // namespace stable_matching
+}  // namespace greedy_algorithms
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void tests() {
+    // Test Case 1
+    std::vector<std::vector<std::uint32_t>> primary_preferences = {{0, 1, 2, 3}, {2, 1, 3, 0}, {1, 2, 0, 3}, {3, 0, 1, 2}};
+    std::vector<std::vector<std::uint32_t>> secondary_preferences = {{1, 0, 2, 3}, {3, 0, 1, 2}, {0, 2, 1, 3}, {1, 2, 0, 3}};
+    assert(greedy_algorithms::stable_matching::gale_shapley(secondary_preferences, primary_preferences) == std::vector<std::uint32_t>({0, 2, 1, 3}));
+
+    // Test Case 2
+    primary_preferences = {{0, 2, 1, 3}, {2, 3, 0, 1}, {3, 1, 2, 0}, {2, 1, 0, 3}};
+    secondary_preferences = {{1, 0, 2, 3}, {3, 0, 1, 2}, {0, 2, 1, 3}, {1, 2, 0, 3}};
+    assert(greedy_algorithms::stable_matching::gale_shapley(secondary_preferences, primary_preferences) == std::vector<std::uint32_t>({0, 3, 1, 2}));
+
+    // Test Case 3
+    primary_preferences = {{0, 1, 2}, {2, 1, 0}, {1, 2, 0}};
+    secondary_preferences = {{1, 0, 2}, {2, 0, 1}, {0, 2, 1}};
+    assert(greedy_algorithms::stable_matching::gale_shapley(secondary_preferences, primary_preferences) == std::vector<std::uint32_t>({0, 2, 1}));
+
+    // Test Case 4
+    primary_preferences = {};
+    secondary_preferences = {};
+    assert(greedy_algorithms::stable_matching::gale_shapley(secondary_preferences, primary_preferences) == std::vector<std::uint32_t>({}));
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    tests(); // Run self-test implementations
+    return 0;
+}

physics/ground_to_ground_projectile_motion.cpp

@@ -10,6 +10,7 @@
  */
 
 #include <cassert>   /// for assert()
+#define _USE_MATH_DEFINES
 #include <cmath>     /// for std::pow(), std::sin(), and std::cos()
 #include <iostream>  /// for IO operations
 
@@ -27,11 +28,12 @@ namespace ground_to_ground_projectile_motion {
 /**
  * @brief Convert radians to degrees
  * @param radian Angle in radians
- * @param PI The definition of the constant PI
  * @returns Angle in degrees
  */
-double degrees_to_radians(double radian, double PI = 3.14) {
-    return (radian * (PI / 180));
+
+double degrees_to_radians(double degrees){
+    double radians = degrees * (M_PI / 180);
+    return radians;
 }
 
 /**

search/binary_search.cpp

@@ -4,16 +4,16 @@
  * algorithm](https://en.wikipedia.org/wiki/Binary_search_algorithm)
  * @details
  * Binary search is a search algorithm that finds the position of a target value
- * within a sorted array. Binary search compares the target value to the middle
- * element of the array. If they are not equal, the half in which the target
+ * within a sorted array.Just like looking for a word in a dictionary, in binary search we compare the target value to the middle
+ * element of the array. If they are not equal, then the half in which the target
  * cannot lie is eliminated and the search continues on the remaining half,
  * again taking the middle element to compare to the target value, and repeating
  * this until the target value is found. If the search ends with the remaining
  * half being empty, the target is not in the array.
  *
  * ### Implementation
  *
- * Binary search works on sorted arrays. Binary search begins by comparing an
+ * Binary search works on sorted arrays. It begins by comparing an
  * element in the middle of the array with the target value. If the target value
  * matches the element, its position in the array is returned. If the target
  * value is less than the element, the search continues in the lower half of
@@ -28,6 +28,7 @@
  * Worst-case time complexity	O(log n)
  * Best-case time complexity	O(1)
  * Average time complexity	    O(log n)
+ * space complexity  0(1)
  * Worst-case space complexity  0(1)
  *
  * @author [Lajat Manekar](https://github.com/Lazeeez)