# FAQ: When is merge sort better than quicksort?

## When should you use merge sort?

Merge Sort is useful for sorting linked lists. 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)

## Is merge sort faster than selection sort?

For example, the mergesort algorithm copies elements back and forth to a temporary array during each merge. For each comparison, it does several times the work. We’d expect a merge sort to be about 40 times faster than a selection sort. (The actual figure, as it turns out, is around 50 times faster.)

## What is the best case running time of merge sort?

Sorting algorithms

Algorithm Data structure Time complexity:Best
Quick sort Array O(n log(n))
Merge sort Array O(n log(n))
Heap sort Array O(n log(n))
Smooth sort Array O(n)

## Why is merge sort faster?

Indeed, it is because merge sort is implemented recursively that makes it faster than the other algorithms we’ve looked at thus far. In part 2 of this series, we’ll look at the runtime complexity of merge sort, how this recursion actually makes it more efficient, and how merge sort stacks up against other algorithms.

## Which sorting algorithm is fastest?

The time complexity of Quicksort is O(n log n) in the best case, O(n log n) in the average case, and O(n^2) in the worst case. But because it has the best performance in the average case for most inputs, Quicksort is generally considered the “fastest” sorting algorithm.

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## What’s the best sorting algorithm?

Quicksort. Quicksort is one of the most efficient sorting algorithms, and this makes of it one of the most used as well. The first thing to do is to select a pivot number, this number will separate the data, on its left are the numbers smaller than it and the greater numbers on the right.

## What is the disadvantage of selection sort?

The primary disadvantage of the selection sort is its poor efficiency when dealing with a huge list of items. Similar to the bubble sort, the selection sort requires n-squared number of steps for sorting n elements.

## Why is insertion sort better?

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 sorting algorithm is best for sorted array?

When the array is almost sorted, insertion sort can be preferred. When order of input is not known, merge sort is preferred as it has worst case time complexity of nlogn and it is stable as well. When the array is sorted, insertion and bubble sort gives complexity of n but quick sort gives complexity of n^2.

## Which is the slowest sorting procedure?

Discussion Forum

Que. Out of the following, the slowest sorting procedure is
b. Heap Sort
c. Shell Sort
d. Bubble Sort

## Is Big O average or worst case?

In short, there is no kind of relationship of the type “big O is used for worst case, Theta for average case”. All types of notation can be (and sometimes are) used when talking about best, average, or worst case of an algorithm.

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## Is Quicksort faster than bubble sort?

Also, for small data set, bubble sort or other simple sorting algorithm usually works faster than more complex algorithms. For example, say bubble sort takes 3ms per iteration while quicksort takes 20ms. So for an array with 10 items. In this case bubble sort takes 10*10*3 = 300ms.

## Is Merge Sort difficult?

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.

## What is a stable sorting algorithm?

Stable sorting algorithms maintain the relative order of records with equal keys (i.e. values). That is, a sorting algorithm is stable if whenever there are two records R and S with the same key and with R appearing before S in the original list, R will appear before S in the sorted list.