#146
Trees into tables
| Difficulty: | Easy |
| Topics: | seqs maps |
Because Clojure's for macro allows you to "walk" over multiple
sequences in a nested fashion, it is excellent for transforming all sorts of
sequences. If you don't want a sequence as your final output (say you want a map),
you are often still best-off using for, because you can produce a sequence and feed
it into a map, for example.
For this problem, your goal is to "flatten" a map of hashmaps. Each key in your
output map should be the "path" (1) that you would have to take in the original
map to get to a value, so for example {1 {2 3}} should result in {[1 2] 3}. You
only need to flatten one level of maps: if one of the values is a map, just leave
it alone.
(1) That is, (get-in original [k1 k2]) should be the same as (get result [k1 k2])
 | (= (__ '{a {p 1, q 2}
b {m 3, n 4}})
'{[a p] 1, [a q] 2
[b m] 3, [b n] 4}) |
| (= (__ '{[1] {a b c d}
[2] {q r s t u v w x}})
'{[[1] a] b, [[1] c] d,
[[2] q] r, [[2] s] t,
[[2] u] v, [[2] w] x}) |
| (= (__ '{m {1 [a b c] 3 nil}})
'{[m 1] [a b c], [m 3] nil}) |