The Algorithm Design Manual

basis cases, namely the specification of the smallest and simplest objects where the decomposition stops.

Permutations are likely the object in question whenever your problem seeks an “arrangement,” “tour,” “ordering,” or “sequence.”

Subsets are likely the object in question whenever your problem seeks a “cluster,” “collection,” “committee,” “group,” “packaging,” or “selection.”

Points are likely the object in question whenever your problems work on “sites,” “positions,” “data records,” or “locations.”

Graphs are likely the object in question whenever you seek a “network,” “circuit,” “web,” or “relationship.”

Polygons and polyhedra are likely the object in question whenever you are working on “shapes,” “regions,” “configurations,” or “boundaries.”

Order does not matter in subsets

Trees are likely the object in question whenever your problem seeks a “hierarchy,” “dominance relationship,” “ancestor/descendant relationship,” or “taxonomy.”

Strings are likely the object in question whenever you are dealing with “text,” “characters,” “patterns,” or “labels.”