From c6a8a6841c7049bd6f26fd0412f9a06360df0cbf Mon Sep 17 00:00:00 2001
From: Swastika Gupta <64654203+Swastyy@users.noreply.github.com>
Date: Sun, 4 Jul 2021 17:18:47 +0530
Subject: [PATCH] Create wave_sort.cpp

---
 sorting/wave_sort.cpp | 92 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 sorting/wave_sort.cpp

diff --git a/sorting/wave_sort.cpp b/sorting/wave_sort.cpp
new file mode 100644
index 000000000..e9f54a929
--- /dev/null
+++ b/sorting/wave_sort.cpp
@@ -0,0 +1,92 @@
+/**
+ * @file
+ * @brief Implementation of [Wave sort] algorithm
+ * @details
+ * Wave Sort is a sorting algorithm that works in \f$O(nlogn)\f$ time assuming the sort function used works in \f$O(nlogn)\f$ time.
+ * @author [Swastika Gupta](https://github.com/swastyy)
+ */
+
+#include <cassert>    /// for assert
+#include <algorithm>  /// for std::is_sorted, std::swap
+#include <iostream>   /// for io operations
+#include <vector>     /// for std::vector
+
+/**
+ * @namespace sorting
+ * @brief Sorting algorithms
+ */
+namespace sorting {
+/**
+ * @namespace wave_sort
+ * @brief Functions for [Wave sort] algorithm
+ */
+namespace wave_sort {
+/**
+ * @brief The main function implements waveSort
+ * @tparam T type of array
+ * @param in_arr array to be sorted
+ * @returns arr the wave sorted array
+ */
+template <typename T>
+std::vector<T> waveSort(const std::vector<T> &in_arr) {
+    std::vector<T> arr(in_arr);
+    int n = sizeof(in_arr)/sizeof(int);
+
+    for (int i=0;i<n;i++) {
+        arr[i] = in_arr[i];
+    }
+    std::sort(arr.begin(),arr.end());
+    for (int i=0; i<n-1; i+=2) { // swap all the adjacent elements
+        std::swap(arr[i], arr[i+1]);
+    }
+    return arr;
+}
+}  // namespace wave_sort
+}  // namespace sorting
+
+/**
+ * @brief Test implementations
+ * @returns void
+ */
+static void test() {
+    // [10, 90, 49, 2, 1, 5, 23] return [2, 1, 10, 5, 49, 23, 90]
+    std::vector<int> array1 = {10, 90, 49, 2, 1, 5, 23};
+    std::cout << "Test 1... ";
+    std::vector<int> arr1 = sorting::wave_sort::waveSort(array1);
+    std::vector<int> o1 = {2, 1, 10, 5, 49, 23, 90};
+    assert(std::equal(arr1.begin(),arr1.end(),o1.begin(),o1.end()));
+    std::cout << "passed" << std::endl;
+
+    // [1, 3, 4, 2, 7, 8] return [2, 1, 4, 3, 8, 7]
+    std::vector<int> array2 = {1, 3, 4, 2, 7, 8};
+    std::cout << "Test 2... ";
+    std::vector<int> arr2 = sorting::wave_sort::waveSort(array2);
+    std::vector<int> o2 = {2, 1, 4, 3, 8, 7};
+    assert(std::equal(arr2.begin(),arr2.end(),o2.begin(),o2.end()));
+    std::cout << "passed" << std::endl;
+
+    // [3, 3, 3, 3] return [3, 3, 3, 3]
+    std::vector<int> array3 = {3, 3, 3, 3};
+    std::cout << "Test 3... ";
+    std::vector<int> arr3 = sorting::wave_sort::waveSort(array3);
+    std::vector<int> o3 = {3, 3, 3, 3};
+    assert(std::equal(arr3.begin(),arr3.end(),o3.begin(),o3.end()));
+    std::cout << "passed" << std::endl;
+
+    // [9, 4, 6, 8, 14, 3] return [4, 3, 8, 6, 14, 9]
+    std::vector<int> array4 = {9, 4, 6, 8, 14, 3};
+    std::cout << "Test 4... ";
+    std::vector<int> arr4 = sorting::wave_sort::waveSort(array4);
+    std::vector<int> o4 = {4, 3, 8, 6, 14, 9};
+    assert(std::equal(arr4.begin(),arr4.end(),o4.begin(),o4.end()));
+    std::cout << "passed" << std::endl;
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    test();  // execute the test
+    return 0;
+}