What is bad about merge sort?
In the worst case, merge sort uses approximately 39\% fewer comparisons than quicksort does in its average case, and in terms of moves, merge sort’s worst case complexity is O(n log n) – the same complexity as quicksort’s best case.
What are the limitations of merge sort?
Disadvantages – Merge Sort The running time of merge sort algorithm is 0(n log n). which turns out to be the worse case. Merge sort algorithm requires additional memory spance of 0(n) for the temporary array TEMP.
What is pivot in merge sort?
pivot – An element in the array that will be used to divide the array in to subarrays. One subarray will have values less than the pivot and the other subarray will have values greater than the pivot.
Why is merge sort not N 2?
Recursion depth Since on every recursion, merge sort divided the list into two, then the number of recursion until we reach the base case is equal to the number of time n can be divided by 2. That is log(n) by definition.
What will be the best and worst cases for merge sort?
Difference between QuickSort and MergeSort
| QUICK SORT | MERGE SORT |
|---|---|
| Worst-case time complexity is O(n2) | Worst-case time complexity is O(n log n) |
| It takes less n space than merge sort | It takes more n space than quicksort |
How do you find the worst case of merge sort?
In order to generate the worst case of merge sort, the merge operation that resulted in above sorted array should result in maximum comparisons. In order to do so, the left and right sub-array involved in merge operation should store alternate elements of sorted array.
What are the advantages and disadvantages of quick sort?
As a first step, Quick Sort chooses one of the items in the array to be sorted as pivot. Then, the array is partitioned on either side of the pivot….Disadvantages
- It is recursive.
- It requires quadratic (i.e., n2) time in the worst-case.
Is merge sort better than bubble sort?
Both have their pros and cons, but ultimately bubble sort quickly becomes less efficient when it comes to sorting larger data sets (or ‘big data’). Where as, Merge Sort becomes more efficient as data sets grow. This makes more sense once you familiarize yourself with Big-O Notation and the concept of time complexity.
What are the worst case time complexity of merge sort and quicksort?
Worst case complexity : The worst case complexity of quick sort is O(n2) as there is need of lot of comparisons in the worst condition. In merge sort, worst case and average case has same complexities O(n log n).
What happens when quicksort algorithm performs its worst case?
When Does the Worst Case of Quicksort Occur? elements. Similarly, when the given input array is sorted reversely and we choose the rightmost element as the pivot element, the worst case occurs. Again, in this case, the pivot elements will split the input array into two unbalanced arrays.
Is merge sort parsimonious?
(b) insertion sort and top-down mergesort are parsimonious Selection sort counterexample: C B A. The keys B and C get compared twice, once in first iteration and once in second iteration.
Why merge sort complexity is Nlogn?
Why is mergesort O(log n)? Mergesort is a divide and conquer algorithm and is O(log n) because the input is repeatedly halved.
How to select median as pivot in quick sort?
Pick median as pivot. The key process in quickSort is partition(). Target of partitions is, given an array and an element x of array as pivot, put x at its correct position in sorted array and put all smaller elements (smaller than x) before x, and put all greater elements (greater than x) after x. All this should be done in linear time.
What is the difference between quick sort and merge sort?
Merge Sort. Like QuickSort, Merge Sort is a Divide and Conquer algorithm. It divides input array in two halves, calls itself for the two halves and then merges the two sorted halves.
How do you pivot an array in quick sort?
QuickSort. Pick median as pivot. The key process in quickSort is partition(). Target of partitions is, given an array and an element x of array as pivot, put x at its correct position in sorted array and put all smaller elements (smaller than x) before x, and put all greater elements (greater than x) after x.
What is the time complexity of merge sort?
Time Complexity: Sorting arrays on different machines. Merge Sort is a recursive algorithm and time complexity can be expressed as following recurrence relation. T (n) = 2T (n/2) + θ (n) The above recurrence can be solved either using the Recurrence Tree method or the Master method.