Handling Duplicate Elements in Merge Sort: Unexpected Infinite Loop in C++
This might be a silly question, but I'm currently implementing the Merge Sort algorithm in C++ to sort an array of integers that may contain duplicate values... However, I'm working with an unexpected infinite loop when dealing with arrays where duplicates are present. My implementation works fine for arrays without duplicates, but when I test it with an array like `{5, 3, 8, 3, 2, 6}`, it gets exploring in a loop. Here’s a snippet of my merge function: ```cpp void merge(int arr[], int left, int mid, int right) { int n1 = mid - left + 1; int n2 = right - mid; int* L = new int[n1]; int* R = new int[n2]; for (int i = 0; i < n1; i++) L[i] = arr[left + i]; for (int j = 0; j < n2; j++) R[j] = arr[mid + 1 + j]; int i = 0, j = 0, k = left; while (i < n1 && j < n2) { if (L[i] <= R[j]) { arr[k++] = L[i++]; } else { arr[k++] = R[j++]; } } while (i < n1) { arr[k++] = L[i++]; } while (j < n2) { arr[k++] = R[j++]; } } ``` The scenario seems to arise during the merging process, particularly when the elements are equal, causing the indices to not increment properly. I tried adding debug statements to track the values of `L[i]` and `R[j]`, and it appears that when duplicates are encountered, the merge function does not progress correctly. I’ve also ensured that I’m freeing up the dynamically allocated memory for `L` and `R` after the merge completes, so memory leaks shouldn’t be an scenario. Can anyone point me in the right direction on how to fix this infinite loop scenario? Is there a best practice for handling duplicates in merge sort? I'm working on a CLI tool that needs to handle this. I'd really appreciate any guidance on this. This is part of a larger API I'm building.