Add example for bucket sort

cpp/algorithms/sorting/CMakeLists.txt

@@ -22,3 +22,4 @@ add_subdirectory(bubble)
 add_subdirectory(heap)
 add_subdirectory(quick)
 add_subdirectory(count)
+add_subdirectory(bucket)

cpp/algorithms/sorting/bucket/CMakeLists.txt

@@ -0,0 +1,17 @@
+###############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: A basic CMakeLists configuration to practice bucket sort           ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+
+cmake_minimum_required(VERSION 3.16)
+project(BucketSort LANGUAGES CXX)
+
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+
+add_executable(bucket-sort "bucket-sort.cpp")
+
+add_library(lib-bucket "lib-bucket.cpp")
+target_link_libraries(bucket-sort lib-bucket)

cpp/algorithms/sorting/bucket/bucket-sort.cpp

@@ -0,0 +1,40 @@
+/*#############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: An example implementation of bucket sort using a custom library    ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+*/
+
+#include "lib-bucket.hpp"
+
+#include <algorithm>
+#include <iostream>
+#include <random>
+#include <vector>
+
+
+int main(const int argc, const char * argv[])
+{
+  srand(time(nullptr));
+  std::vector<float> array(ARRAY_LENGTH);
+  std::generate(array.begin(), array.end(),
+                [](){ return static_cast<float>(rand() % 1000) * 0.1f;}
+                );
+
+  auto print = [](std::vector<float> array) {
+    for (const auto &i : array) {
+      std::cout << i << ", ";
+    }
+    std::cout << std::endl;
+  };
+
+  std::cout << "Unsorted array: \n";
+  print(array);
+
+  BucketSort(array);
+
+  std::cout << "Sorted array: \n";
+  print(array);
+}

cpp/algorithms/sorting/bucket/lib-bucket.cpp

@@ -0,0 +1,42 @@
+/*#############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: An example implementation of bucket sort using a custom library    ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+*/
+
+#include "lib-bucket.hpp"
+
+#include <algorithm>
+#include <list>
+#include <vector>
+
+
+void BucketSort(std::vector<float> &array)
+{
+  // For this example, we need an array of linked lists
+  // + Each value of this array will be referred to as a bucket
+  // + Each list stores the values that fall within the range of that bucket
+  std::vector<std::list<float>> bucketArray(BUCKET_ARRAY_LENGTH);
+
+  // Truncation to zero will always floor the result of division
+  // + If the bucket contains negative values, convert them to their absolutes
+  // + Run BucketSort on the abs values, then convert them back to negative
+  // ++ For a mixed-bag of negative and positive, track which values you absolute
+  // ++ Then only negate those values after BucketSort
+  for (const auto & value : array) {
+    bucketArray[value / static_cast<float>(bucketArray.size())].push_back(value);
+  }
+
+  // Track the last used index in the final sorted array; Starting at 0
+  int currentIndex = 0;
+  // Sort each bucket in the bucketArray
+  for (std::list<float> &bucket : bucketArray) {
+    bucket.sort();
+    // After sorting each bucket, rewrite values in-order to final sorted array
+    for (const auto &value : bucket) array[currentIndex++] = value;
+  }
+
+}

cpp/algorithms/sorting/bucket/lib-bucket.hpp

@@ -0,0 +1,23 @@
+/*#############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: An example implementation of bucket sort using a custom library    ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+*/
+
+#ifndef LIB_BUCKET_HPP
+#define LIB_BUCKET_HPP
+
+#include <list>
+#include <vector>
+
+// For this example double the size of the array to increase chance of collision
+#define ARRAY_LENGTH 20
+// Define how many buckets we want to use
+#define BUCKET_ARRAY_LENGTH 10
+
+void BucketSort(std::vector<float> &array);
+
+#endif // LIB_BUCKET_HPP