How to resolve the algorithm Dutch national flag problem step by step in the Raku programming language

Published on 12 May 2024 09:40 PM
#Raku

How to resolve the algorithm Dutch national flag problem step by step in the Raku programming language

Table of Contents

Problem Statement

The Dutch national flag is composed of three coloured bands in the order:

The problem posed by Edsger Dijkstra is: When the problem was first posed, Dijkstra then went on to successively refine a solution, minimising the number of swaps and the number of times the colour of a ball needed to determined and restricting the balls to end in an array, ...

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Dutch national flag problem step by step in the Raku programming language

Source code in the raku programming language

enum NL ;
my @colors;

sub how'bout (&this-way) {
    sub show {
        say @colors;
        say "Ordered: ", [<=] @colors;
    }

    @colors = NL.roll(20);
    show;
    this-way;
    show;
    say '';
}

say "Using functional sort";
how'bout { @colors = sort *.value, @colors }

say "Using in-place sort";
how'bout { @colors .= sort: *.value }

say "Using a Bag";
how'bout { @colors = flat red, white, blue Zxx bag(@colors».key) }

say "Using the classify method";
how'bout { @colors = flat (.list for %(@colors.classify: *.value){0,1,2}) }

say "Using multiple greps";
how'bout { @colors = flat (.grep(red), .grep(white), .grep(blue) given @colors) }

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