Over <integers>, choose \b[`s = (-)`, `c = flip (-)`, and `a = b = 0`]. The <left fold> and <right fold> both compute the negative of the <sum> of a finite <list>. The combining <functions> differ: `s 1 2 = -1`, whereas `c 1 2 = 1`.

Solution

Past exam of the year 1 of the computer science course of the University of Oxford / 2019 / Functional programming, design and analysis of algorithms / 1 / d / Solution

 Solution (source code)