It is a measure of how an algorithm responds to a data size.
It classifies performance as input size grows. “O” indicates the order of operation: time scale to perform an operation
Many algorithm and DS have more than an O
|O(1)||Constant Time||Looking up a single element in an array|
|O(log n)||Logarrithmic||Finding an item is a sorted array with a binary search|
|O(n)||Linear time||Searching an unsorted array for a specific value|
|O(n log n)||Log linear||Complex sorting algorithm like heapsort and merge sort|
|O(n2)||Quadratic||Simple sorting algorithm like bubble sort|