How quickly is a new element inserted into the buffer endpoint in memory?

Inserting a new element at the end of a memory buffer is usually very fast — on the order of O(1) time, that is, constant time. This is because the buffer in memory is a contiguous block, and adding an element to the end simply requires writing the value into the next free cell and updating the end pointer.

However, if the buffer is implemented as a dynamic array and has reached its maximum size, it may be necessary to allocate a new memory block and copy data, which will increase the insertion time at that moment.