Another brief recursion excursion to Hanoi
Steven Minsker · ACM SIGCSE Bulletin · 2008
We propose another simple Towers of Hanoi variant, a hybrid between classical Hanoi and linear Hanoi, in which the rules governing movement depend on ring color. An optimal algorithm is presented. The problem and its heavily recursive solution are not difficult; perhaps one of its more interesting facets is that the optimality proof uses simultaneous induction on four statements. This paper can be viewed as similar in purpose and spirit to the author's previous work [1]; the goal here is again to present a fun example of potential usefulness in teaching discrete mathematics and data structures courses.