Habibur Rahman (https://www.facebook.com/mmhabib89)
BUBT University Bangladesh
http://www.bubt.edu.bd/
The average cost of a successful search is about the same as the worst case where an item is not
found in the array, both being roughly equal to log N.
So, the average and the worst case cost of binary search, in big-O notation, is O(log N)
That depends on the list size an how often a search is made for a non existent list item. Doubling the list size from 1024 to 2048 will only add one more iteration to the search in a worst case scenario. This holds true for each time the list is doubled. What may not be evident is that a binary search gets more efficient as the list gets bigger (not to confused with quicker).
The best case complexity is O(1) i.e if the element to search is the middle element. The average and worst case time complexity are O(log n).
If the array is unsorted, the complexity is O(n) for the worst case. Otherwise O(log n) using binary search.
Binary search is a log n type of search, because the number of operations required to find an element is proportional to the log base 2 of the number of elements. This is because binary search is a successive halving operation, where each step cuts the number of choices in half. This is a log base 2 sequence.
binary search
Merge sort is O(n log n) for both best case and average case scenarios.
Linear search takes linear time with a worst case of O(n) for n items, and an average of O(n/2). Binary search takes logarithmic time, with a worst and average case of O(n log n). Binary search is therefore faster on average.
If the array is unsorted, the complexity is O(n) for the worst case. Otherwise O(log n) using binary search.
Binary search is a log n type of search, because the number of operations required to find an element is proportional to the log base 2 of the number of elements. This is because binary search is a successive halving operation, where each step cuts the number of choices in half. This is a log base 2 sequence.
binary search
Merge sort is O(n log n) for both best case and average case scenarios.
Linear search takes linear time with a worst case of O(n) for n items, and an average of O(n/2). Binary search takes logarithmic time, with a worst and average case of O(n log n). Binary search is therefore faster on average.
The best case for a binary search is finding the target item on the first look into the data structure, so O(1). The worst case for a binary search is searching for an item which is not in the data. In this case, each time the algorithm did not find the target, it would eliminate half the list to search through, so O(log n).
In the worst case a binary search tree is linear and has a height equal to the number of nodes. so h=O(h).
In linear search, the searched key will be compared with each element of the array from the beginning and terminate comparing when the searched key is found or the array is reached. Here time complexity in worst case and average case is O (n). To find an element quickly we use divide and conquer method by using binary search algorithm. Here probed region is reduced from n to n/2. Time complexity is O (log2 n), but here the array should be sorted. But in interpolation search the probed region is reduced from n to n1/2. If the array elements are uniformly distributed the average case complexity is O (log2 (log2n)). Am also searching for hashing to compare & contrast with above.
the compexity of linear search in worst case is f(n) = n+1
For a list with n elements, the expected cost is the same as the worst-case cost, which is O(n). The average cost will be O(n/2). However, if the list is ordered by probability and geometrically distributed, the complexity becomes constant, O(1). Compare with a binary search which has a cost of O(log n).
Time complexity Best case: The best case complexity of bubble sort is O(n). When sorting is not required, all the elements are already sorted. Average case: The average case complexity of bubble sort is O(n*n). It occurs when the elements are jumbled, neither properly ascending nor descending. Worst case: The worst-case complexity of bubble sort is O(n*n). It occurs when the array elements are needed to be sorted in reverse order. Space complexity In the bubble sort algorithm, space complexity is O(1) as an extra variable is needed for swapping.
These are terms given to the various scenarios which can be encountered by an algorithm. The best case scenario for an algorithm is the arrangement of data for which this algorithm performs best. Take a binary search for example. The best case scenario for this search is that the target value is at the very center of the data you're searching. So the best case time complexity for this would be O(1). The worst case scenario, on the other hand, describes the absolute worst set of input for a given algorithm. Let's look at a quicksort, which can perform terribly if you always choose the smallest or largest element of a sublist for the pivot value. This will cause quicksort to degenerate to O(n2). Discounting the best and worst cases, we usually want to look at the average performance of an algorithm. These are the cases for which the algorithm performs "normally."