Q44: What are the Time Complexities (Big O) of common Array operations?
push()/pop(): $O(1)$ (end of array).unshift()/shift(): $O(n)$ (requires re-indexing elements).indexOf()/includes(): $O(n)$ linear search.sort(): $O(n \log n)$ average time complexity.
Key Takeaways
- Adding/removing from start (
shift/unshift) is $O(n)$. - Array access by numeric index (
arr[i]) is $O(1)$.
Knowledge Check
Why is array.unshift() an O(n) operation whereas array.push() is O(1)?