Task — Sort letters

You are given two arrays, @letters and @weights. Write a script to sort the given array @letters based on the @weights.

Examples

Example 1
Input: @letters = ('R', 'E', 'P', 'L')
       @weights = (3, 2, 1, 4)
Output: PERL

Example 2
Input: @letters = ('A', 'U', 'R', 'K')
       @weights = (2, 4, 1, 3)
Output: RAKU

Example 3
Input: @letters = ('O', 'H', 'Y', 'N', 'P', 'T')
       @weights = (5, 4, 2, 6, 1, 3)
Output: PYTHON

Analysis

Inspection of the examples reveals that:

sorted[weights[j]] = letters[j]

And allowing for Perl's zero-based arrays that is exactly my solution.

I could have made it strictly one line by using @_ directly rather than copying the arguments of the subroutine into local arrays, but

$sorted[$_[1]->[$_] - 1] = $_[0]->[$_] 
   for 0 .. @{$_[0]} - 1;

is not very easy to read (but it does work).

Try it 

#!/usr/bin/perl

# Blog: http://ccgi.campbellsmiths.force9.co.uk/challenge

use v5.26;    # The Weekly Challenge - 2024-07-22
use utf8;     # Week 279 - task 1 - Sort letters
use warnings; # Peter Campbell Smith
binmode STDOUT, ':utf8';

sort_letters(['R', 'E', 'P', 'L'], [3, 2, 1, 4]);
sort_letters(['A', 'U', 'R', 'K'], [2, 4, 1, 3]);
sort_letters(['a', 'C', 'e', 'e', 'g', 'h', 'l', 'l', 'n'], [3, 1, 6, 9, 8, 2, 4, 5, 7]);

sub sort_letters {
    
    my (@letters, @weights, @sorted);
    
    @letters = @{$_[0]};
    @weights = @{$_[1]};

    # rearrange the letters
    $sorted[$weights[$_] - 1] = $letters[$_] for 0 .. @letters - 1;

    printf(qq[\nInput:  \@letters = ('%s'), \@weights = (%s)\n], join(qq[', '], @letters), join(', ', @weights));
    printf(qq[Output: %s\n], join('', @sorted));
}

Output

Input:  @letters = ('R', 'E', 'P', 'L'), 
        @weights = (3, 2, 1, 4)
Output: PERL

Input:  @letters = ('A', 'U', 'R', 'K'), 
        @weights = (2, 4, 1, 3)
Output: RAKU

Input:  @letters = ('a', 'C', 'e', 'e', 'g', 'h', 'l', 
        'l', 'n'), @weights = (3, 1, 6, 9, 8, 2, 4, 5, 7)
Output: Challenge