column the final column of table shows comparisonswhich we'll return to in moment it' harder to calculate the number of copies and comparisons when is not multiple of but these numbers fall between those that are power of for itemsthere are total copiesand for items total copies number of comparisons in the mergesort algorithmthe number of comparisons is always somewhat less than the number of copies how much lessassuming the number of items is power of for each individual merging operationthe maximum number of comparisons is always one less than the number of items being mergedand the minimum is half the number of items being merged you can see why this is true in figure which shows two possibilities when trying to merge arrays of items each figure maximum and minimum comparisons in the first casethe items interleaveand comparisons must be made to merge them in the second caseall the items in one array are smaller than all the items in the otherso only comparisons must be made there are many merges for each sortso we must add the comparisons for each one referring to figure you can see that merge operations are required to sort items the number of items being merged and the resulting number of comparisons is shown in table table comparisons involved in sorting items step number totals number of items being merged( maximum comparisons( - minimum