How fast is insertion sort

Radix sort is a special sort whose performance greatly relies on the data type. It is best used when the data items are fixed-width and this fact can be leveraged, which makes it great for sorting lists of integers but not for sorting lists of general strings. I have seen work someone did to make it efficient for sorting bit floating-point, but it did heavily leverage the internal storage of the floating-point number.

It actually depends on what type of list you are using: even though Insetrion Sort's worst-case time is O n 2 it is an approximation meaning that it does not apply for small or nearly sorted lists. Quick sort uses extra overhead because of all the recursive functions. This is why you should privilege Insertion sort over the divide and conquer sorting algorithms like merge sort and quick sort when the problem is small.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Why is insertion sort so fast compared to other sorting algorithms? Ask Question. Asked 4 years, 8 months ago. Active 4 years, 8 months ago. Viewed 1k times. Here is my code for the Insertion Sort and Timer functions in Python 3.

Improve this question. Lee A. Lee 29 6 6 bronze badges. How long is the list? Also, timing things with time isn't ideal, use the timeit module.

You can look at the complexity of different sorting algorithms here. It makes the comparison useless, unless you are targeting a very specific n size. Actually, looking in a bit more detail, you only call the sort algorithm once for a list of unspecified size. Even if you don't want to use timeit , you have such a limited test case that it's impossible for you to use this approach to benchmark your algorithms.

It looks like you're sorting the list, then timing sorting again. But the second time, the list is already sorted which is the absolute best case for insertion sort. Add a comment. Active Oldest Votes. Quick sort is more efficient and works faster than merge sort in case of smaller array size or datasets.

Sorting method : The quick sort is internal sorting method where the data is sorted in main memory. The main difference between quicksort and merge sort is that the quicksort sorts the elements by comparing each element with an element called a pivot while merge sort divides the array into two subarrays again and again until one element is left. Merge Sort is a stable sort which means that the same element in an array maintain their original positions with respect to each other.

Overall time complexity of Merge sort is O nLogn. It is more efficient as it is in worst case also the runtime is O nlogn The space complexity of Merge sort is O n. The merge sort algorithm is a divide and conquer sorting algorithm that has a time complexity of O n log n. Therefore, it is an extremely versatile and reliable sorting algorithm.

Surprisingly enough, it is also not that difficult to implement and understand. Insertion sort has a fast best-case running time and is a good sorting algorithm to use if the input list is already mostly sorted. For larger or more unordered lists, an algorithm with a faster worst and average-case running time, such as mergesort, would be a better choice.

Which of the following is good for sorting arrays having less than elements? Explanation: The insertion sort is good for sorting small arrays.

It sorts smaller arrays faster than any other sorting algorithm. How many passes does an insertion sort algorithm consist of? Explanation: An insertion algorithm consists of N-1 passes when an array of N elements is given.

Insertion sort is the sorting mechanism where the sorted array is built having one item at a time. The array elements are compared with each other sequentially and then arranged simultaneously in some particular order.

How much faster is insertion sort with a element array than with a element array? The time efficiency of selection sort is quadratic, so there are a number of sorting techniques which have better time complexity than selection sort. Merge sort is a recursive algorithm that continually splits a list in half. If the list is empty or has one item, it is sorted by definition the base case. Overview of quicksort. The way that quicksort uses divide-and-conquer is a little different from how merge sort does.

In merge sort, the divide step does hardly anything, and all the real work happens in the combine step. Quick Sort is also a cache friendly sorting algorithm as it has good locality of reference when used for arrays. Quick Sort is also tail recursive, therefore tail call optimizations is done.