##### best sorting algorithm for reverse sorted array

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The interval between the elements is gradually decreased based on the sequence used. The answer, as is often the case for such questions, is "it depends". To sort an array in reverse/decreasing order, you can use std::sort algorithm provided by STL. The default Arrays.sort() implementation in Java 7 â¦ Example: Gif from GfyCat Code: This means the equation for Merge Sort would look as follows: $$T(n) = 2T(\frac{n}{2})+cn$$ Average and Worst case sorting occurs when arrays are reverse sorted, Best case sorting occurs when arrays are already sorted. Uses: Insertion sort is used when number of elements is small. Shell Sort is a variation of Insertion Sort. And it takes minimum time (Order of n) when elements are already sorted. Due to its simplicity, it is always used to introduce the concept of sorting. Quick Sort Algorithm. ; Sorting In place: Yes.It does not uses extra space to sort the elements. It sorts the elements of a container in the range pointed by the specified iterators using a comparator. Sorting algorithms have a lower bound and an upper bound on the number of comparisons( n log n worst-case for merge and heap sorts, n log n average case for quick sort). In Merge sort, we divide the array recursively in two halves, until each sub-array contains a single element, and then we merge the sub-array in a way that it results into a sorted array. At the end of the day though, whatever the best sorting algorithm really is depends on the input (and who you ask). If T(n) is runtime of the algorithm when sorting an array of the length n, Merge Sort would run twice for arrays that are half the length of the original array. In INSERTION-SORT, the best case occurs if the array is already sorted. The merge step takes O(n) memory, so k=1. So if we have a=2, b=2. Mergesort is up there with the fastest standard sort algorithms. Stable: Yes.It is stable sorting algorithm. Sorting is a very classic problem of reordering items (that can be compared, e.g. ... a sorted array is returned. The general goal of a sorting algorithm is to minimize the number of comparisons. With this algorithm, the array is sorted at a specific interval based on the chosen sequence. If you don't care about memory, a simple Mergesort would suffice. The default comparator used is std::less> which sorts the container in ascending order using operator<. Merge Sort is one of the best examples of Divide & Conquer algorithm. Quicksort is one of the most efficient ways of sorting elements in computer systems. In the most general case, you'd go with an algorithm that happens to have the best average or best worst-case number of comparisons. If you want the best sorting algorithm that runs under assumption that âthe data is already sortedâ, then the best algorithm is âdo nothingâ which runs in no time. 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