Question

我想找到节点之间的最近距离。

以下是我的示例数据：

节点，x，y

例如，从节点1到节点2的最近距离为5.我想找到距节点2,3,4,5的所有节点的最近距离。

我如何在Perl中实现这一点？

这是我到目前为止所做的：

use strict;
use warnings;
use Data::Dumper;

open(IN , "<" , "sample.txt" ) or die "Can't open this file.";

my @two_dimentional_array;
while (my $line=<IN>)
{
    my @arr_line=split (" *, *" , $line);
        my @one_dimentional_array;
        push @one_dimentional_array , @arr_line;
        push @two_dimentional_array, [@arr_line];
}

for(my $i=0 ; $i<=$#two_dimentional_array ; $i++)
{
    my ($n_1 , $X_1 , $y_1)=@{$two_dimentional_array[$i]};
    for (my $j=0 ; $j<=$#two_dimentional_array ; $j++)
    {
        my ($n_2 , $X_2 , $y_2)=@{$two_dimentional_array[$j]};

        chomp($y_1);
        chomp($y_2);
        if($n_1 != $n_2)
        {
            my $distance=sqrt(($X_2-$X_1)**2 + ($y_2-$y_1)**2);
            print "Distance ".$distance." from node ".$n_1." to node ".$n_2."\n";
        }
    }
}
#print Dumper(\@two_dimentional_array);

Answer 1

#!/usr/bin/perl

use strict;
use warnings;

my (@data, @temp, @result);

sub calc {
    my ($a, $b) = @_;
    my $dat = 0;
    $dat += ($a->[$_] - $b->[$_]) ** 2 for (1,2);
    return sqrt $dat;
}

while (<DATA>) {
    push @data, [split /,?\s+/];
}

for my $x (@data) {
    for my $y (@data) {
        push @temp, [calc($x, $y), $x, $y] if ($x->[0] > $y->[0]);
    }
}

@result = sort { $a->[0] <=> $b->[0]; } @temp;
printf "%-18s => [%s], [%s]\n", $_->[0],
    join(', ', @{$_->[1]}), join(', ', @{$_->[2]}) for @result;

__DATA__
1,  3,  5
2,  6,  9
3,  13, 15
4,  16, 20
5,  30, 50

输出：

5                  => [2, 6, 9], [1, 3, 5]
5.8309518948453    => [4, 16, 20], [3, 13, 15]
9.21954445729289   => [3, 13, 15], [2, 6, 9]
14.142135623731    => [3, 13, 15], [1, 3, 5]
14.8660687473185   => [4, 16, 20], [2, 6, 9]
19.8494332412792   => [4, 16, 20], [1, 3, 5]
33.1058907144937   => [5, 30, 50], [4, 16, 20]
38.9101529166874   => [5, 30, 50], [3, 13, 15]
47.5078940808788   => [5, 30, 50], [2, 6, 9]
52.4785670536077   => [5, 30, 50], [1, 3, 5]

Answer 2

此代码将找到相距最小距离的第一对。

use strict;
use warnings;

# @data contains (node number, x, y) from the file
#
my @data;

open my $fh, '<', 'sample.data' or die $!;

while (<$fh>) {
  my @node = /\d+/g;
  push @data, \@node if @node;
}

# @min contains (first node number, second node number, distance)
# for the most recently-found minimum distance
#
my @min;

for my $node1 (0 .. $#data-1) {
  for my $node2 ($node1+1 .. $#data-1) {
    my $dist;
    $dist += ( $data[$node2][$_] - $data[$node1][$_] ) ** 2 for 1, 2;
    $dist = sqrt $dist;
    @min = ( $data[$node1][0], $data[$node2][0], $dist ) unless @min and $min[2] <= $dist;
  }
}

printf "%d to %d = %f\n", @min;

<强>输出

1 to 2 = 5.000000

找到节点之间的最近距离

2 个答案: