Comment by b20000

in my 25 years of software development, 90% of the time, you don't need to optimize the code and the worst solution in time complexity is totally fine. then there is another 8% of situations where trading in space for time complexity is the solution, i.e. using lookup tables. the remaining 1-2% of the cases you might need a combination of some data structures or containers from the STL or boost (in the case of C++). I've never had to roll some special version of a data structure or container or algorithm myself from scratch, and I work on some really complicated real time software.