How to Efficiently Handle Duplicate Elements in a Custom Quick Sort Implementation in C++?
I'm having trouble with I'm confused about I've searched everywhere and can't find a clear answer... I'm currently working on a custom implementation of the Quick Sort algorithm in C++, and I've encountered an unexpected performance scenario when handling duplicate elements in the array. My implementation is running into problems where the sorting time increases significantly with arrays that contain many repeated values. For instance, sorting an array like `{3, 3, 3, 1, 2, 3, 5, 3}` is taking much longer than I anticipated. Here's a snippet of my current implementation: ```cpp #include <iostream> #include <vector> using namespace std; int partition(vector<int>& arr, int low, int high) { int pivot = arr[high]; int i = low - 1; for (int j = low; j < high; j++) { if (arr[j] < pivot) { i++; swap(arr[i], arr[j]); } } swap(arr[i + 1], arr[high]); return i + 1; } void quickSort(vector<int>& arr, int low, int high) { if (low < high) { int pi = partition(arr, low, high); quickSort(arr, low, pi - 1); quickSort(arr, pi + 1, high); } } int main() { vector<int> arr = {3, 3, 3, 1, 2, 3, 5, 3}; quickSort(arr, 0, arr.size() - 1); for (auto num : arr) { cout << num << " "; } return 0; } ``` While the sorting works correctly, I noticed a considerable performance degradation in terms of time complexity as the number of duplicates increases. I'm currently using the Lomuto partition scheme, which I suspect might not be the best choice for this scenario. I've tried switching to Hoare's partition scheme, but I still faced performance optimization. Is there a more efficient way to handle duplicates in Quick Sort? Should I consider switching to a different sorting algorithm entirely for arrays with many repeated elements? Any suggestions or optimizations would be appreciated! For context: I'm using C++ on Ubuntu. What's the best practice here? For reference, this is a production microservice. Is this even possible? Is there a better approach?