A glyph contour contains points set {p}, a point contains tuple (x,y,on_curve).
Now, think about this need, converting contour of glyph X, for example, into to two contour parts or two strokes, point set of each stroke is similar with contour of glyph \ and /, topologically? Forgive my mouthful description.
Other examples (symbols at right of -> are shapes how these parts look like):
A -> / \ -
B -> | 3 or | ) )
C -> C
D -> | )
E -> |---
F -> |--
G -> C-|
PS: I don't know whether there any algorithm exists for this need. I use python and hope to make it with Python programming.