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

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2021-05-29 16:12:08 +00:00
/*#############################################################################
## 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;
}
}