How to determine the time required to insert an element at the end of a slice in programming language?

In Go language, a slice is a structure that contains a pointer to an array, a length, and a capacity.

Inserting an element at the end of a slice usually occurs through the append operation:

slice = append(slice, newElement)

The time of insertion depends on whether the current capacity of the slice is sufficient for the new element:

• If the capacity is enough, append simply writes the element to the next free slot — an O(1) operation.
• If the capacity is not enough, a new array with increased capacity is allocated, old elements are copied, and the new element is added — an O(n) operation, where n is the current length of the slice.

Thus, the amortized time for inserting at the end of a slice is O(1), although individual operations can be more expensive due to memory reallocation.