not as pretty, but simpler and pretty enough?
(":"0@i.@# (,~ #&'-')"1 0 ]) 0 1 2 2 1 1 2 2 3
0
-1
--2
--3
-4
-5
--6
--7
---8
J has several functions built in to process trees that are represented as
nested box structures, and so may be useful in converting from various
representations to and from such boxed structures. Or more interesting to me,
but I need more thought on this.
On Friday, August 7, 2020, 09:19:22 a.m. EDT, ethiejiesa via Programming
<[email protected]> wrote:
Do you know a slick way of pretty-printing a tree given its depth vector
representation?
A vector represents a tree if and only if it satisfies the following:
NB. Tree valid? First node is root node (depth 0), only one root node,
NB. and all nodes are exactly one deeper than their parent
tv=: 0&=@{. *. *./@(>&0)@}. *. 1 *./@:>: +/\^:_1
The goal is to produce a nice visualization given a valid depth vector. For
example, given (d=: 0 1 2 2 1 1 2 2 3), something like this would be ideal:
o
|-o
| |-o
| +-o
|-o
+-o
|-o
+-o
+-o
About the best I can do in a single line is this:
NB. Tree print
tp=: (, LF&,)/@({&' |o-')@((3&*@=/ |:@}.@(,/)@(,:"1&|:) 2&*@=/ +. >/) ~.)
tp d
o
|-o
| |-o
| | |-o
|-o
| |-o
| | |-o
|-o
| |-o
| | |-o
Trimming the branches, however, is giving me a lot of grief. Can you do better?
I am looking for terse one-liners but am open to alternative visualizations.
Producing segments of "trimmed branches" is a nice little sub-problem. It
corresponds to finding finding "catenaries", i.e. runs of integers capped on
the left and right by n, where the intervening integers "droop below" n, i.e.
satisfy (>:n).
Looking forward to your ideas!
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