以首个元素为基准的QuickSort无法正常运行求助

Hey there! Totally get wanting to work through this yourself instead of copying code—figuring out these bugs is where you’ll really lock in how QuickSort works.

Since your tail-pivot version runs smoothly, the issue is almost certainly in the small but critical adjustments needed when switching to a first-element pivot. Here are the most common pitfalls to keep an eye on while you share your code:

• Misaligned partition logic: When your pivot sits at the start of the array, the way you move left/right pointers and swap elements needs to shift. For example, if you previously started the right pointer at the end and moved left, you might now need to adjust which pointer moves first, or how you handle swaps when you find elements out of order.
• Incorrect recursive bounds: After partitioning, the pivot lands in its correct sorted position—but if you miscalculate the left/right subarray bounds (like re-including the pivot, or cutting off part of the array), you’ll end up with unsorted sections or even infinite recursion.
• Botched duplicate value handling: If your list has elements equal to the pivot, using strict comparisons (> or <) instead of inclusive ones (>= or <=) can cause pointers to get stuck in loops or leave elements unpartitioned.

To help you pinpoint exactly what’s off, could you share:

1. Your first-element pivot QuickSort code (including the partition function)
2. A sample input list you tested, the output you got, and the expected sorted result?

Once we have that, we can walk through the logic step by step and fix the bug together without just handing you a pre-written solution.

内容的提问来源于stack exchange，提问作者Lukas