Can you give an example of an algorithm complexity estimate that was incorrect or insufficient?

Error in algorithm complexity estimation is often related to simplified assumptions about data behavior or ignoring worst-case scenarios.

For example, when using insertion sort, it is often said that the algorithm runs in O(n) if the data is almost sorted. However, if the data is random or sorted in reverse order, the complexity becomes O(n²). Not considering these cases can lead to an underestimation.

In iOS development, an example can be given with UITableView and the dequeueReusableCell method. If one assumes that cell reuse is always efficient and ignores cases where many new cells are created (for example, during fast scrolling with different cell types), the memory and time costs can be underestimated.

Therefore, it is important to consider all scenarios and data characteristics when estimating complexity and performance.