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Why does merge sort take extra space?
Unlike some (efficient) implementations of quicksort, merge sort is a stable sort. Merge sort’s most common implementation does not sort in place; therefore, the memory size of the input must be allocated for the sorted output to be stored in (see below for variations that need only n/2 extra spaces).
Can we do merge sort without extra space?
1 Answer. Yes, it’s possible to perform an in-place merge sort. That does not mean it doesn’t require any extra memory, since the recursion still takes O(lg n) stack space (just like quicksort).
Can we do merge in constant space complexity?
MergeSort time Complexity is O(nlgn) which is a fundamental knowledge. Merge Sort space complexity will always be O(n) including with arrays. If you draw the space tree out, it will seem as though the space complexity is O(nlgn).
Does merge sort use a lot of space?
Merge Sort is a stable sort which means that the same element in an array maintain their original positions with respect to each other. The space complexity of Merge sort is O(n). This means that this algorithm takes a lot of space and may slower down operations for the last data sets .
How much extra memory does merge sort use?
With insertion sort you need only one temporary element. With merge sort you need at least an array with N/2 temporary elements. But a trivial implementation will need a temporary array with N elements. So insertion sort requires O(1) extra memory, while merge sort requires O(N) additional memory.
Is merge sort a stable algorithm?
Yes
Merge sort/Stable
What are the space requirements for merge sort?
Space requirements of a merge-sort. However, in most implementations the space is linear in the size of the array. That means n for the first level, n/2 for the second, n/4 for the third, etc. By the time you are at the bottom of your recursion, this series adds up to about 2n, which is linear.
How is merge sort implemented in an array?
Therefore merge operation of merge sort can be implemented without extra space for linked lists. In arrays, we can do random access as elements are contiguous in memory. Let us say we have an integer (4-byte) array A and let the address of A [0] be x then to access A [i], we can directly access the memory at (x + i*4).
How is merge sort slower than other sort algorithms?
1 Slower comparative to the other sort algorithms for smaller tasks. 2 Merge sort algorithm requires an additional memory space of 0 (n) for the temporary array. 3 It goes through the whole process even if the array is sorted.
How to merge two halves in merge sort?
Call mergeSort for second half: Call mergeSort (arr, m+1, r) 4. Merge the two halves sorted in step 2 and 3: Call merge (arr, l, m, r) The following diagram from wikipedia shows the complete merge sort process for an example array {38, 27, 43, 3, 9, 82, 10}.