If it were me, I'd probably consult Cracking The Coding Interview[1], and the Robert Sedgewick Algorithms in C++ [2][3] books. That and maybe spend some time practicing on Leetcode, Hacker Rank, Project Euler, etc. Skiena's Algorithm Design Manual[4] could also be good.

[1]: https://www.amazon.com/Cracking-Coding-Interview-Programming...

[2]: https://www.amazon.com/Algorithms-Parts-1-4-Fundamentals-Str...

[3]: https://www.amazon.com/Algorithms-Part-Graph-3rd-Pt-5/dp/020...

[4]: https://www.amazon.com/Algorithm-Design-Manual-Steven-Skiena...