Quicksort has O(n2) worst-case runtime and O(nlogn) average case runtime. However, it’s superior to merge sort in many scenarios because many factors influence an algorithm’s runtime, and, when taking them all together, quicksort wins out. In particular, the often-quoted runtime of sorting algorithms refers to the number of comparisons or the number of swaps necessary … Read more
You need to make a compare function which compares 2 strings and use that as the last argument in qsort. read more about the function here http://www.cplusplus.com/reference/cstdlib/qsort/?kw=qsort
Using ^ below a letter to indicate it’s a pivot, and * to indicate it’s already been pivoted. If a partition has odd length, I pick the “rounded down middle” (partition length 4 would have the 2nd item as pivot). Note how in the 4th line, there are two R‘s, with one of them being … Read more
Your code is not right: it does not do a stable partition of the array. Imagine your array is 100, 33, 333, 22, 222, 11 After the stable partitioning around the first element, it should become 33, 22, 11, 100, 333, 222 // 33, 22, and 11 in the same order as in the original … Read more