Unique Occurrences
You are given an array of integers,
@ints
.Write a script to return
1
if the number of occurrences of each value in the given array is unique or0
otherwise.
The following algorithm solves the problem:
 get a list of all available numbers
 for each number compare it to each list element, creating a matrix
 sum up each row to get the count per number
 classify this list
 reduce the classified list with a logical and
This task is well suited for BQN to show its’ array processing strength:


The first step of the algorithm is represented by the innermost brackets
(∊/⊢)
. Here I used an instrument of tacit programming, a train. The argument
gets passed to classify, returning a list of the same length. However, the first
occurrence of each number in the original argument is replaced with a one,
otherwise a zero. The right function of this train is simply the right identity
function and returns its argument unaltered.
Replicate takes
both results and filters the list. This function is itself a left part of the
train (∊/⊢)=⌜⊢
which implements step two. Now that a suitable matrix has been
created, +´˘
sums them up. Notice the need to use the
Cells modifier to sum row
wise. Step four is just applying classify to the occurrence counts. The
atop combinator is necessary,
else the logical reduction, classify and the right bracket expression would form
a train. Then the last step is achieved by applying the
fold modifier to the
and function.
In contrast a Raku implementation:


Raku’s Bag class makes this task a
breeze. It automatically sums up each occurrences for each element and makes the
result easily accessible in a dictionary like manner. If each value is unique,
applying .unique.elems
is the same as directly using the method .elems
. The
function uses this to determine the return value.
Dictionary Rank
You are given a word,
$word
.Write a script to compute the dictionary rank of the given word.

