M.H. Albert, R.J. Nowakowski and D. Wolfe

Lessons in Play,

second edition, CRC Press, 2019.

Aaron N. Siegel,

Combinatorial Game Theory,

AMS, 2013.

Elwyn R. Berlekamp, John H. Conway and Richard K. Guy,

Winning Ways for your Mathematical Plays, Academic Press, two volumes, 1982.

Second edition: AK Peters, four volumes, 2001-2004.

Fun with Algorithms, conference series, Lecture Notes in Computer Science.

D.P. Williamson and D.B. Shmoys,

The design of approximation algorithms, Cambridge University Press, 2011

Amy N. Langville & Carl D. Meyer,

Who's #1?
The Science of Rating and Ranking,
Princeton University Press, 2012

T.H. Cormen, C.E. Leiserson, R.L. Rivest and C. Stein,

Introduction to Algorithms (3rd ed.), 2009, MIT Press and McGraw-Hill

R.A. Hearn and E.D. Demaine,

Games, Puzzles, & Computation, Peters, 2009

Donald E. Knuth, The Art of Computer Programming, Volume 4, Combinatorial Algorithms, 2011

And even older: 2008: DNA String Algorithms. And 2002: Advanced BioComputing.