Weekly Challenge 202

Challenge 202

My answers will also be on github.

Task One

Given a list of integers, write a script to print 1 if there are THREE consecutive odds in the given array, otherwise print 0.

Task Two

In a list of altitudes, return the first widest valley.

Solution to Task One

On this I return 0 if there aren't three neighboring odds, otherwise pass through to check that they are consecutive.

use v5.30.0;
my @array1 = (1,5,3,6);
my @array2 = (2,6,3,5);
my @array3 = (1,2,3,4);
my @array4 = (2,3,5,7);
my @test = (\@array1, \@array2,\@array3,\@array4);    
sub are_three_odds {
    my @list = @_;
    my @ind;
    for (0 .. $#list - 2) {
    push @ind, $_ if ( ($list[$_] % 2 == 1) && ($list[$_ + 1] % 2 == 1) && ($list[$_ + 2] % 2 == 1) );
    }
    return 0 unless (@ind);
    foreach (@ind) {
    my @set = ($list[$_],$list[$_+1],$list[$_+2]);
    @set = sort {$a <=> $b} @set;
    if ( ($set[2] - $set[1]) == ($set[1] - $set[0])) {
        return 1;
    }
    }
    return 0;
}

for (0 .. $#test) {
    my @array = @{$test[$_]};
    say "Input: (".join(",",@array).")";
    say "Output: " . are_three_odds(@array);
}

Solution to Task Two

This I was able to manage with a few flags and one pass of the array. Once we stop increasing, the valley is over. Push all valleys to a collection then return the longest.

use v5.30.0;
my @array1 = (1, 5, 5, 2, 8);
my @array2 = (2,6,8,5);
my @array3 = (9,8,13,13,2,2,15,17);
my @array4 = (2,1,2,1,3);
my @array5 = (1,3,3,2,1,2,3,3,2);
my @test = (\@array1,\@array2,\@array3,\@array4,\@array5);
for my $ref (@test) {
    my @array = @$ref;
    my @valley;           # push an array ref to each valley here.
    my $begin_index = 0;
    my $incr_flag = 0;      # flag after descent is complete.
    for (0 .. $#array - 1) {
    if ($incr_flag) {
        if ( $array[$_ + 1] < $array[$_] ) {
        push @valley, [ @array[$begin_index .. $_] ];
        $begin_index = $_;
        for my $i (1 .. $_) { # check if it was level
            if ( $array[$_] == $array[$_ - $i] ) {
            $begin_index--;
            } else {
            last;
            }
        }
        $incr_flag = 0;
        }
    } else {
        if ( $array[$_ + 1] > $array[$_] ) {
        $incr_flag = 1;
        }
    }
    }
    push @valley, [ @array[$begin_index .. $#array] ];
    my $max = 0;
    my $ind;
    for (0 .. $#valley) {
    if (scalar @{$valley[$_]} > $max) {
        $max = scalar @{$valley[$_]};
        $ind = $_;
    }
    }
    say "Input: @array";
    say "Output: @{$valley[$ind]}";
    say "-" x 10;
}