Rosetta Code

Inventory sequence

Revision as of 05:14, 11 May 2023 by Wherrera (talk | contribs) (→‎{{header|Python}})

To build the inventory sequence, first take inventory of what numbers are already in the sequence, then, starting with 0 add the count of each number in turn to the end of the sequence. When you reach a number that has a count of 0, stop, add the 0 to the end of the sequence, and then restart the inventory from 0.

Inventory sequence is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.


E.G.
Start taking inventory; how many 0s are there? 0. Add a 0 to the end of the sequence and restart the inventory. (0)
How many 0s are there? 1. Add a 1 to the end of the sequence. How many 1s are there? 1. Add a 1 to the end of the sequence. How many 2s are there? 0. Add a 0 to the end of the sequence and restart the inventory. (0 1 1 0)
and so on.


Task
  • Find and display the first 100 elements of the sequence.
  • Find and display the position and value of the first element greater than or equal to 1000.


Stretch
  • Find and display the position and value of the first element greater than or equal to 2000, 3000 ... 10,000.
  • Plot a graph of the first 10,000 elements of the sequence.


See also


Python

''' rosettacode.org/wiki/Inventory_sequence '''
from collections import Counter
from matplotlib.pyplot import plot

def inventory_sequence(terms):
    ''' From the code by Branicky at oeis.org/A342585 '''
    num, alst, inventory = 0, [0], Counter([0])
    for n in range(2, terms+1):
        c = inventory[num]
        num = 0 if c == 0 else num + 1
        alst.append(c)
        inventory.update([c])
    return alst

biglist = inventory_sequence(201_790)
thresholds = [1000 * j for j in range(1, 11)]

for i, k in enumerate(biglist):
    if i < 100:
        print(f'{k:<4}', end='\n' if (i + 1) % 20 == 0 else '')
    elif k >= thresholds[0]:
        print(f'\nFirst element >= {thresholds.pop(0):5}: {k:5} in position {i:6}')
        if len(thresholds) == 0:
               break

plot(biglist[:10_000], linewidth=0.3)
Output:
0   1   1   0   2   2   2   0   3   2   4   1   1   0   4   4   4   1   4   0   
5   5   4   1   6   2   1   0   6   7   5   1   6   3   3   1   0   7   9   5   
3   6   4   4   2   0   8   9   6   4   9   4   5   2   1   3   0   9   10  7   
5   10  6   6   3   1   4   2   0   10  11  8   6   11  6   9   3   2   5   3   
2   0   11  11  10  8   11  7   9   4   3   6   4   5   0   12  11  10  9   13  

First element >=  1000:  1001 in position  24255

First element >=  2000:  2009 in position  43301

First element >=  3000:  3001 in position  61708

First element >=  4000:  4003 in position  81456

First element >=  5000:  5021 in position  98704

First element >=  6000:  6009 in position 121342

First element >=  7000:  7035 in position 151756

First element >=  8000:  8036 in position 168804

First element >=  9000:  9014 in position 184428

First element >= 10000: 10007 in position 201788
 


Raku

use Lingua::EN::Numbers;

my ($i, %i) = 0;

my @inventory = (^∞).map: {
    my $count = %i{$i} // 0;
    $i = $count ?? $i+1 !! 0;
    ++%i{$count};
    $count
}

say "Inventory sequence, first 100 elements:\n" ~
  @inventory[^100].batch(20)».fmt("%2d").join: "\n";

say '';

for (1..10).map: * × 1000 {
    my $k = @inventory.first: * >= $_, :k;
    printf "First element >= %6s is %6s in position: %s\n",
      .&comma, @inventory[$k].&comma, comma $k;
}


use SVG;
use SVG::Plot;

my @x = ^10000;

'Inventory-raku.svg'.IO.spurt:
 SVG.serialize: SVG::Plot.new(
    background  => 'white',
    width       => 1000,
    height      => 600,
    plot-width  => 950,
    plot-height => 550,
    x           => @x,
    values      => [@inventory[@x],],
    title       => "Inventory Sequence - First {+@x} values (zero indexed)",
).plot: :lines;
Output:
Inventory sequence, first 100 elements:
 0  1  1  0  2  2  2  0  3  2  4  1  1  0  4  4  4  1  4  0
 5  5  4  1  6  2  1  0  6  7  5  1  6  3  3  1  0  7  9  5
 3  6  4  4  2  0  8  9  6  4  9  4  5  2  1  3  0  9 10  7
 5 10  6  6  3  1  4  2  0 10 11  8  6 11  6  9  3  2  5  3
 2  0 11 11 10  8 11  7  9  4  3  6  4  5  0 12 11 10  9 13

First element >=  1,000 is  1,001 in position: 24,255
First element >=  2,000 is  2,009 in position: 43,301
First element >=  3,000 is  3,001 in position: 61,708
First element >=  4,000 is  4,003 in position: 81,456
First element >=  5,000 is  5,021 in position: 98,704
First element >=  6,000 is  6,009 in position: 121,342
First element >=  7,000 is  7,035 in position: 151,756
First element >=  8,000 is  8,036 in position: 168,804
First element >=  9,000 is  9,014 in position: 184,428
First element >= 10,000 is 10,007 in position: 201,788

converted to a .png to reduce size for display here:

 
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