CareerCup

Hash map:
On average Search and Delete are O( 1 + n/ # of bucket )
Because there might be more than one element have the same hash value.
And we have to do the search similar to the array inside that bucket.

Worse case for Search and Delete are O(n)
e.g. everything map to the same hash value.

Binary tree:
O(logn) "If balanced"
If the binary is not balanced, it can form a shape identical to array and take O(n)
To avoid that, some self-balancing algorithm is required.
Like RB-tree

Arrays:
Insert, delete and search are all O(n)

Hashmaps:
Insert and Delete O(1) whereas search is O(n)

Binary tree - all are O(lg n)

arrays should have O(1) time complexity. please correct if am wrong.
In linked list case it should be O(n)

^good soln .