use strict;
use warnings;

use 5.014;

use Term::ANSIColor qw{ :constants };

open my $inFH, q{<}, \ <<EOD or die $!;
01
02 04
06 04 09
05 01 07 02
EOD

=pod
06
-----
12
03 09
-----
01
02 04
06 04 09
05 01 07 02
-----
75
95 64
17 47 82
18 35 87 10
20 04 82 47 65
19 01 23 75 03 34
88 02 77 73 07 63 67
99 65 04 28 06 16 70 92
41 41 26 56 83 40 80 70 33
41 48 72 33 47 32 37 16 94 29
53 71 44 65 25 43 91 52 97 51 14
70 11 33 28 77 73 17 78 39 68 17 57
91 71 52 38 17 14 91 43 58 50 27 29 48
63 66 04 68 89 53 67 30 73 16 69 87 40 31
04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
=cut

my @idxLR  = ( 0, 0, 1 );
my @pathLR = qw{ L L R };

my @lines;

while ( <$inFH> )
{
    chomp;
    push @lines, [
       map { { val => $_, sum => undef } } split
       ];
}

close $inFH or die $!;

if ( scalar @lines == 1 )
{
    say qq{Minimum path sum is - $lines[ 0 ]->[ 0 ]->{ val }};
    say  q{            No path};
}
elsif ( scalar @lines == 2 )
{
    my $compIdx =
       $lines[ 1 ]->[ 1 ]->{ val } <=> $lines[ 1 ]->[ 0 ]->{ val };
    say
       qq{Minimum path sum is - },
       $lines[ 0 ]->[ 0 ]->{ val } +
       $lines[ 1 ]->[ $idxLR[ $compIdx ] ]->{ val };
    say
       qq{            Path is - $pathLR[ $compIdx ]};
}
else
{
    do {
       $_->{ sum }  = $_->{ val };
       $_->{ path } = [];
       } for @{ $lines[ -1 ] };
    foreach my $lineIdx ( reverse 0 .. $#lines - 1 )
    {
        my $raLine = $lines[ $lineIdx ];
        foreach my $itemIdx ( 0 .. $#{ $raLine } )
        {
            my $compIdx =
               $lines[ $lineIdx + 1 ]->[ $itemIdx + 1 ]->{ sum }
               <=>
               $lines[ $lineIdx + 1 ]->[ $itemIdx ]->{ sum };
            $raLine->[ $itemIdx ]->{ sum }  =
               $raLine->[ $itemIdx ]->{ val } +
               $lines[ $lineIdx + 1 ]
                  ->[ $itemIdx + $idxLR[ $compIdx ] ]
                  ->{ sum };
            $raLine->[ $itemIdx ]->{ path } = [
               $pathLR[ $compIdx ],
               @{ $lines[ $lineIdx + 1 ]
                  ->[ $itemIdx + $idxLR[ $compIdx ] ]
                  ->{ path } }
                  ];
        }
    }
    my @pathElems = ( 0 );
    push @pathElems, m{L} ? $pathElems[ -1 ] : $pathElems[ -1 ] + 1
       for @{ $lines[ 0 ]->[ 0 ]->{ path } };;

    say qq{Minimum path sum is - $lines[ 0 ]->[ 0 ]->{ sum }};
    say  q{            Path is - T-},
       join q{-}, @{ $lines[ 0 ]->[ 0 ]->{ path } };
    say  q{       Elements are - },
       join q{-}, @pathElems;
    say q{};

    my $nElems = scalar( @lines ) * 2 - 1;
    my $fmt    = q{%2s} x $nElems;
    $fmt      .= qq{\n};

    for my $lineIdx ( 0 .. $#lines )
    {
        printf $fmt,
           ( q{  } ) x ( $#lines - $lineIdx ),
           sub {
               my @arr =
                  map {
                      $_ == $pathElems[ $lineIdx ]
                      ? RED . $_[ $_ ] . RESET
                      : $_[ $_ ]
                      } 0 .. $#_;
               splice @arr, $_, 0, q{  } for reverse 1 .. $#arr;
               return @arr;
               }->( map { $_->{ val } } @{ $lines[ $lineIdx ] } ),
           ( q{  } ) x ( $#lines - $lineIdx );
    }
}

##</code><code>##

Minimum path sum is - 8
            Path is - T-L-R-L
       Elements are - 0-0-1-1

      01      
    02  04    
  06  04  09  
05  01  07  02