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|
#!perl
###############################################################################
=comment
Perl Weekly Challenge 116
=========================
TASK #2
-------
*Sum of Squares*
Submitted by: Mohammad Meraj Zia
You are given a number $N >= 10.
Write a script to find out if the given number $N is such that sum of squares
of all digits is a perfect square. Print 1 if it is otherwise 0.
Example
Input: $N = 34
Output: 1 as 3^2 + 4^2 => 9 + 16 => 25 => 5^2
Input: $N = 50
Output: 1 as 5^2 + 0^2 => 25 + 0 => 25 => 5^2
Input: $N = 52
Output: 0 as 5^2 + 2^2 => 25 + 4 => 29
=cut
###############################################################################
#--------------------------------------#
# Copyright © 2021 PerlMonk Athanasius #
#--------------------------------------#
#==============================================================================
=comment
Input Argument $N
-----------------
Although it is probably intended that $N be an integer, this is not explicitly
stated in the Task Description and is not really necessary. This script accepts
any real number >= 10, and includes any digits following the decimal point
along with the digits that come before. The decimal point (if any) is ignored.
For example:
Input: $N = 14.22
Output: 1 as 1^2 + 4^2 + 2^2 + 2^2 = 1 + 16 + 4 + 4 = 25 = 5^2
Output
------
The required output (1 or 0) is followed by an explanation as per the Examples.
If this explanation is not wanted, the constant $SHOW should be set to a false
value.
Algorithm
---------
This is straightforward: split $N into its component digits, square each digit,
and sum the squares. The sum is itself a perfect square if and only if its
square root is an integer.
=cut
#==============================================================================
use strict;
use warnings;
use Const::Fast;
use Regexp::Common qw( number );
const my $SHOW => 1;
const my $USAGE =>
"Usage:
perl $0 <N>
<N> A number greater than or equal to 10\n";
#------------------------------------------------------------------------------
BEGIN
#------------------------------------------------------------------------------
{
$| = 1;
print "\nChallenge 116, Task #2: Sum of Squares (Perl)\n\n";
}
#==============================================================================
MAIN:
#==============================================================================
{
my $N = parse_command_line();
print "Input: \$N = $N\n";
my @digits = grep { !/\./ } split //, $N;
my @squares = map { $_ * $_ } @digits;
my $sum = 0;
$sum += $_ for @squares;
my $root = perfect_square_root( $sum );
printf 'Output: %d', $root ? 1 : 0;
if ($SHOW)
{
my $terms = join ' + ', map { "$_^2" } @digits;
my $squares = join ' + ', @squares;
print ' as ' . join( ' = ', $terms, $squares, $sum ) .
($root ? " = $root^2" : ' which is not a perfect square');
}
print "\n";
}
#------------------------------------------------------------------------------
sub perfect_square_root
#------------------------------------------------------------------------------
{
my ($N) = @_;
my $root = int( sqrt( $N ) + 0.5 );
# Return the square root if $N is a perfect square, or undef otherwise
return ($root * $root) == $N ? $root : undef;
}
#------------------------------------------------------------------------------
sub parse_command_line
#------------------------------------------------------------------------------
{
my $args = scalar @ARGV;
$args == 1 or error( "Expected 1 command line argument, found $args" );
my $N = $ARGV[ 0 ];
$N =~ / ^ $RE{num}{real} $ /x
or error( qq["$N" is not a valid real number] );
$N += 0; # Normalize: e.g., 010 --> 10
$N >= 10 or error( "$N is less than 10" );
return $N;
}
#------------------------------------------------------------------------------
sub error
#------------------------------------------------------------------------------
{
my ($message) = @_;
die "ERROR: $message\n$USAGE";
}
###############################################################################
|
