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-rw-r--r--challenge-102/bob-lied/c/ch-1.c82
-rwxr-xr-xchallenge-102/bob-lied/perl/ch-1.pl154
-rw-r--r--challenge-102/cheok-yin-fung/perl/ch-1.pl14
-rw-r--r--challenge-102/james-smith/perl/ch-1.pl6
-rw-r--r--challenge-102/paulo-custodio/ada/ch_1.adb24
-rw-r--r--challenge-102/paulo-custodio/ada/ch_2.adb22
-rw-r--r--challenge-102/paulo-custodio/basic/ch-1.bas60
-rw-r--r--challenge-102/paulo-custodio/basic/ch-2.bas42
-rw-r--r--challenge-102/paulo-custodio/cpp/ch-2.cpp2
-rw-r--r--challenge-102/paulo-custodio/lua/ch-1.lua43
-rw-r--r--challenge-102/paulo-custodio/lua/ch-2.lua46
-rw-r--r--challenge-102/paulo-custodio/perl/ch-1.pl38
-rw-r--r--challenge-102/paulo-custodio/perl/ch-2.pl38
-rw-r--r--challenge-102/paulo-custodio/python/ch-1.py36
-rw-r--r--challenge-102/paulo-custodio/python/ch-2.py44
-rw-r--r--challenge-102/yet-ebreo/perl/ch-2.pl37
16 files changed, 572 insertions, 116 deletions
diff --git a/challenge-102/bob-lied/c/ch-1.c b/challenge-102/bob-lied/c/ch-1.c
new file mode 100644
index 0000000000..1ff39d59ec
--- /dev/null
+++ b/challenge-102/bob-lied/c/ch-1.c
@@ -0,0 +1,82 @@
+/* vim:set ts=4 sw=4 sts=4 et ai wm=0 nu syntax=c: */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+int verbose = 1;
+
+int mightBeRare[10] = { 1, 0, 1, 1, 0, 1, 0, 1, 1, 0 };
+
+int mightBeSquare[10] = { 1, 1, 0, 0, 1, 1, 1, 0, 0, 1 };
+
+long
+reverse(long r)
+{
+ long r1 = 0;
+ while ( r )
+ {
+ r1 = r1 * 10 + r%10;
+ r /= 10;
+ }
+ return r1;
+}
+
+
+int
+main(int argc, char **argv)
+{
+ int N;
+
+ N = atoi(argv[1]);
+
+ int isNodd = N % 2;
+
+ long scale = pow(10, (N-1));
+ long endOfRange = pow(10, N);
+
+ for ( long r = scale ; r < endOfRange ; r++ )
+ {
+ // Rare numbers can never start with an odd digit.
+ if ( (r / scale ) % 2 )
+ {
+ r += scale;
+ }
+
+// if ( r % 10000000 == 0 ) printf("%ld\n", r);
+
+ if ( ! mightBeRare[ r % 10 ] )
+ {
+ continue;
+ }
+
+ long r1 = reverse(r);
+
+ long y2 = r - r1;
+ if ( y2 < 0 ) continue; // Can't be a square
+
+ long x2 = r + r1;
+
+ if ( !( mightBeSquare[ x2%10] && mightBeSquare[ y2%10 ] ) ) continue;
+
+ if ( isNodd )
+ {
+ if ( y2 % 1089 ) continue;
+ }
+ else
+ {
+ if ( x2 % 121 ) continue;
+ }
+
+ double x = sqrt(x2);
+ if ( x != (long)(x) ) continue;
+
+ double y = sqrt(y2);
+ if ( y != (long)(y) ) continue;
+
+ printf("N=%d R=%ld\n", N, r);
+ }
+
+
+ exit(0);
+}
diff --git a/challenge-102/bob-lied/perl/ch-1.pl b/challenge-102/bob-lied/perl/ch-1.pl
new file mode 100755
index 0000000000..4b9007cd1d
--- /dev/null
+++ b/challenge-102/bob-lied/perl/ch-1.pl
@@ -0,0 +1,154 @@
+#!/usr/bin/env perl
+# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
+#=============================================================================
+# ch-1.pl
+#=============================================================================
+# Copyright (c) 2021, Bob Lied
+#=============================================================================
+# Perl Weekly Challenge 102, Task #1, Rare Numbers
+#
+# You are given a positive integer $N.
+# Write a script to generate all Rare numbers of size $N if exists.
+# http://www.shyamsundergupta.com/rare.htm
+# The web site lists several constraints that can be used to limit the search.
+# Also discussed at https://rosettacode.org/wiki/Talk:Rare_numbers
+# Examples
+# (a) 2 digits: 65
+# (b) 6 digits: 621770
+# (c) 9 digits: 281089082
+#
+# From the reference web site:
+# The numbers, which gives a perfect square on adding as well as subtracting
+# its reverse are rare and hence termed as Rare Numbers.
+#
+# If R is a positive integer and R1 is the integer obtained from R by writing
+# its decimal digits in reverse order, then if R + R1 and R - R1 both are
+# perfect square then R is termed as Rare Number.
+#
+# So for R to be a Rare Number we must have
+# R + R1 = X^2 and R - R1 = Y^2
+#
+# For example: For R=65, R1=56
+# R+R1 = 65+56 = 121 = 11^2 AND R-R1 = 65 - 56 = 9 = 3^2
+#
+#=============================================================================
+
+use strict;
+use warnings;
+use 5.020;
+
+use experimental qw/ signatures /;
+
+use Getopt::Long;
+
+my $doTest = 0;
+my $verbose = 0;
+GetOptions("test" => \$doTest, "verbose" => \&verbose);
+
+my $N = shift;
+
+# On my MacBook M1, perl 5.32, 8 takes about 7 seconds and 9 takes about 1:15
+# 10 is probably feasible, maybe 11 for the giftedly patient, but beyond that
+# needs some kind of parallelism or an algorithm I wasn't able to think of.
+die Usage() unless defined $N && $N > 1 && $N < 20;
+warn "Expect this to take a long time ..." if $N > 8;
+
+# The last digit can never be 1,4,6,9
+my @mightBeRare = ( 1, 0, 1, 1, 0, 1, 0, 1, 1, 0 );
+
+# A perfect square can never end in 2,3,7,8
+my @mightBeSquare = ( 1, 1, 0, 0, 1, 1, 1, 0, 0, 1 );
+
+my $isNodd = $N % 2; # Optimization possible for even or odd digits.
+
+# Cache results of square root test here.
+my %knownSquare;
+
+# For example, if N = 3, max is 1000, but we want 100 at a time.
+my $scale = 10**($N-1);
+
+# Rare numbers can never start with an odd digit, so work on
+# only groups that start with an even digit.
+# Creates pairs of start and end.
+my @boundary = map { [ $_ * 2 * $scale, $_ * 2 * $scale + $scale - 1 ] } 1..4;
+
+# Use faster integer math everywhere except where we need the square root.
+use integer;
+
+for my $bound ( @boundary )
+{
+ my $endOfRange = $bound->[1]; # Hoist array access out of loop processing.
+ R: for ( my $r = $bound->[0] ; $r <= $endOfRange ; $r++ )
+ {
+ # say "$r ", scalar(time()) if $r % 10000000 == 0; # Progress mark
+
+ # The last digit can never be 1,4,6,9
+ next unless $mightBeRare[ $r%10 ];
+
+ my $r1;
+ $r1 = reverse($r); # String beats math
+ ##{ use integer;
+ ## my $n = $r; $r1 = 0;
+ ## while ( $n )
+ ## {
+ ## $r1 = $r1 * 10 + $n%10;
+ ## $n /= 10;
+ ## }
+ ##}
+
+ my $y2 = $r - $r1;
+ next if $y2 < 0; # No imaginary numbers.
+ next unless $mightBeSquare[ $y2 % 10];
+
+ my $x2 = $r + $r1;
+ next unless $mightBeSquare[ $x2 % 10];
+
+ # If R consist of odd number of digits, then R-R1 must be divisible by 11.
+ # Since R-R1 is always divisible by 9, So 1089 (33^2) must be a factor of Y2.
+ #
+ # If R consist of even number of digits, then R+R1 must be divisible by 11,
+ # So 121 must be a factor of X2.
+ if ( $isNodd )
+ {
+ next if $y2 % 1089;
+ }
+ else
+ {
+ next if $x2 % 121;
+ }
+
+ # Save the expensive square root computation for last.
+
+ # Caching wasn't effective. Either the overhead of hash lookup was not
+ # much better than the cost of the sqrt function, or there aren't many
+ # cache hits. And memory could blow up for large N.
+ # if ( exists $knownSquare{$x2} )
+ # {
+ # next unless $knownSquare{$x2};
+ # }
+ # else
+ # {
+ # my $x = sqrt($x2);
+ # next unless ($knownSquare{$x2} = (int($x) == $x));
+ # }
+
+ # if ( exists $knownSquare{$y2} )
+ # {
+ # next unless $knownSquare{$y2};
+ # }
+ # else
+ # {
+ # my $y = sqrt($y2);
+ # next unless ($knownSquare{$y2} = (int($y) == $y));
+ # }
+
+ { no integer;
+ my $x = sqrt($x2);
+ next R unless int($x) == $x;
+ my $y = sqrt($y2);
+ next R unless int($y) == $y;
+ }
+
+ say "R: $r";
+ }
+}
diff --git a/challenge-102/cheok-yin-fung/perl/ch-1.pl b/challenge-102/cheok-yin-fung/perl/ch-1.pl
index eab209da06..2a6a02127e 100644
--- a/challenge-102/cheok-yin-fung/perl/ch-1.pl
+++ b/challenge-102/cheok-yin-fung/perl/ch-1.pl
@@ -55,3 +55,17 @@ for my $k ($bN..$eN) {
# reasonable time for length = 7 ,
# be patient for length = 8 (one term, which is palindromic)
# over 2 min and killed for length = 9 ...
+
+=pod
+// add on March 8th
+$ time perl ch-1.pl 9
+200040002
+204060402
+242484242
+281089082
+291080192
+
+real 10m21.188s
+user 10m19.621s
+sys 0m0.084s
+=cut
diff --git a/challenge-102/james-smith/perl/ch-1.pl b/challenge-102/james-smith/perl/ch-1.pl
index 187ed6b95b..dcfb31af4d 100644
--- a/challenge-102/james-smith/perl/ch-1.pl
+++ b/challenge-102/james-smith/perl/ch-1.pl
@@ -41,10 +41,10 @@ sub rare_numbers {
my $x = shift;
return () if $F[$x%9]; ## Digit sum is wrong...
my $y = reverse $x;
- return () if $x == $y; ## Musn't be the same back and forth
- return $y if $x<$y && is_sq($x+$y) && is_sq($y-$x);
+ return () if $x == $y || ! is_sq($x+$y); ## Musn't be the same back and forth
+ return $y if $x<$y && is_sq($y-$x);
+ return $x if $y<$x && is_sq($x-$y);
## Check both ways round!
- return $x if $y<$x && is_sq($x+$y) && is_sq($x-$y);
return ();
}
diff --git a/challenge-102/paulo-custodio/ada/ch_1.adb b/challenge-102/paulo-custodio/ada/ch_1.adb
index b680983748..a785727689 100644
--- a/challenge-102/paulo-custodio/ada/ch_1.adb
+++ b/challenge-102/paulo-custodio/ada/ch_1.adb
@@ -1,23 +1,23 @@
-- Challenge 102
---
+--
-- TASK #1 › Rare Numbers
-- Submitted by: Mohammad S Anwar
---
+--
-- You are given a positive integer $N.
---
--- Write a script to generate all Rare numbers of size $N if exists. Please
+--
+-- Write a script to generate all Rare numbers of size $N if exists. Please
-- checkout the page for more information about it.
-- Examples
---
+--
-- (a) 2 digits: 65
-- (b) 6 digits: 621770
-- (c) 9 digits: 281089082
with Ada.Command_Line;
-with Ada.Strings.Fixed;
+with Ada.Strings.Fixed;
use Ada.Strings.Fixed;
-with Ada.Text_IO;
- use Ada.Text_IO;
+with Ada.Text_IO;
+ use Ada.Text_IO;
with Ada.Numerics.Generic_Elementary_Functions;
procedure ch_1 is
@@ -29,8 +29,8 @@ procedure ch_1 is
-- Sqrt
package Value_Functions is new Ada.Numerics.Generic_Elementary_Functions(Float);
- use Value_Functions;
-
+ use Value_Functions;
+
-- convert 1234 to 4321
function invert_number(a0 : Integer) return integer is
a : Integer := a0;
@@ -54,7 +54,7 @@ procedure ch_1 is
return False;
end if;
end is_perfect_square;
-
+
-- print all rare numbers with n digits
procedure print_rare_numbers(n : Integer) is
r1 : Integer;
@@ -71,7 +71,7 @@ procedure ch_1 is
end if;
end loop;
end print_rare_numbers;
-
+
begin
print_rare_numbers(Integer'Value(CL.Argument(1)));
end ch_1;
diff --git a/challenge-102/paulo-custodio/ada/ch_2.adb b/challenge-102/paulo-custodio/ada/ch_2.adb
index 7eb1656ec9..48fb10aa2d 100644
--- a/challenge-102/paulo-custodio/ada/ch_2.adb
+++ b/challenge-102/paulo-custodio/ada/ch_2.adb
@@ -1,23 +1,23 @@
-- Challenge 102
---
+--
-- TASK #2 › Hash-counting String
-- Submitted by: Stuart Little
---
+--
-- You are given a positive integer $N.
---
+--
-- Write a script to produce Hash-counting string of that length.
---
+--
-- The definition of a hash-counting string is as follows:
-- - the string consists only of digits 0-9 and hashes, ‘#’
-- - there are no two consecutive hashes: ‘##’ does not appear in your string
-- - the last character is a hash
--- - the number immediately preceding each hash (if it exists) is the position
+-- - the number immediately preceding each hash (if it exists) is the position
-- of that hash in the string, with the position being counted up from 1
---
--- It can be shown that for every positive integer N there is exactly one such
+--
+-- It can be shown that for every positive integer N there is exactly one such
-- length-N string.
-- Examples:
---
+--
-- (a) "#" is the counting string of length 1
-- (b) "2#" is the counting string of length 2
-- (c) "#3#" is the string of length 3
@@ -26,7 +26,7 @@
with Ada.Command_Line;
with Ada.Strings.Fixed; use Ada.Strings.Fixed;
-with Ada.Text_IO; use Ada.Text_IO;
+with Ada.Text_IO; use Ada.Text_IO;
procedure ch_2 is
-- command line arguments
@@ -49,7 +49,7 @@ procedure ch_2 is
end loop;
return res;
end hash_count;
-
-begin
+
+begin
Put_Line(hash_count(Integer'Value(CL.Argument(1))));
end ch_2;
diff --git a/challenge-102/paulo-custodio/basic/ch-1.bas b/challenge-102/paulo-custodio/basic/ch-1.bas
index b33e778d9a..161682f7a8 100644
--- a/challenge-102/paulo-custodio/basic/ch-1.bas
+++ b/challenge-102/paulo-custodio/basic/ch-1.bas
@@ -1,52 +1,52 @@
' Challenge 102
-'
+'
' TASK #1 > Rare Numbers
' Submitted by: Mohammad S Anwar
-'
+'
' You are given a positive integer $N.
-'
-' Write a script to generate all Rare numbers of size $N if exists. Please
+'
+' Write a script to generate all Rare numbers of size $N if exists. Please
' checkout the page for more information about it.
' Examples
-'
+'
' (a) 2 digits: 65
' (b) 6 digits: 621770
' (c) 9 digits: 281089082
' convert 1234 to 4321
function invert_number(a as Integer) as Integer
- dim a1 as Integer
- do while a<>0
- a1 = a1*10 + (a mod 10)
- a = int(a / 10)
- loop
- invert_number = a1
+ dim a1 as Integer
+ do while a<>0
+ a1 = a1*10 + (a mod 10)
+ a = int(a / 10)
+ loop
+ invert_number = a1
end function
' check if number is a perfect square
function is_perfect_square(n as Integer) as Boolean
- dim sq as Double
- sq = sqr(CDbl(n))
- if int(sq)^2=n then
- is_perfect_square = True
- else
- is_perfect_square = False
- end if
-end function
+ dim sq as Double
+ sq = sqr(CDbl(n))
+ if int(sq)^2=n then
+ is_perfect_square = True
+ else
+ is_perfect_square = False
+ end if
+end function
' print all rare numbers with n digits
sub print_rare_numbers(n as Integer)
- dim r as Integer, r1 as Integer
- for r=10^(n-1) to 10^(n)-1
- r1 = invert_number(r)
- if is_perfect_square(r+r1) then
- if r>=r1 then
- if is_perfect_square(r-r1) then
- print trim(str(r))
- end if
- end if
- end if
- next
+ dim r as Integer, r1 as Integer
+ for r=10^(n-1) to 10^(n)-1
+ r1 = invert_number(r)
+ if is_perfect_square(r+r1) then
+ if r>=r1 then
+ if is_perfect_square(r-r1) then
+ print trim(str(r))
+ end if
+ end if
+ end if
+ next
end sub
' main
diff --git a/challenge-102/paulo-custodio/basic/ch-2.bas b/challenge-102/paulo-custodio/basic/ch-2.bas
index 9987f13b4e..34380d02aa 100644
--- a/challenge-102/paulo-custodio/basic/ch-2.bas
+++ b/challenge-102/paulo-custodio/basic/ch-2.bas
@@ -1,23 +1,23 @@
' Challenge 102
-'
+'
' TASK #2 › Hash-counting String
' Submitted by: Stuart Little
-'
+'
' You are given a positive integer $N.
-'
+'
' Write a script to produce Hash-counting string of that length.
-'
+'
' The definition of a hash-counting string is as follows:
' - the string consists only of digits 0-9 and hashes, ‘#’
' - there are no two consecutive hashes: ‘##’ does not appear in your string
' - the last character is a hash
-' - the number immediately preceding each hash (if it exists) is the position
+' - the number immediately preceding each hash (if it exists) is the position
' of that hash in the string, with the position being counted up from 1
-'
-' It can be shown that for every positive integer N there is exactly one such
+'
+' It can be shown that for every positive integer N there is exactly one such
' length-N string.
' Examples:
-'
+'
' (a) "#" is the counting string of length 1
' (b) "2#" is the counting string of length 2
' (c) "#3#" is the string of length 3
@@ -25,19 +25,19 @@
' (e) "2#4#6#8#11#14#" is the string of length 14
function hash_count(n as Integer) as String
- Dim res as String, i as Integer, p as Integer
- i = n
- do while i>0
- p = i
- res = "#" & res
- i = i-1
- do while i>0 and p<>0
- res = chr(asc("0") + (p mod 10)) & res
- p = int(p / 10)
- i = i-1
- loop
- loop
- hash_count = res
+ Dim res as String, i as Integer, p as Integer
+ i = n
+ do while i>0
+ p = i
+ res = "#" & res
+ i = i-1
+ do while i>0 and p<>0
+ res = chr(asc("0") + (p mod 10)) & res
+ p = int(p / 10)
+ i = i-1
+ loop
+ loop
+ hash_count = res
end function
'main
diff --git a/challenge-102/paulo-custodio/cpp/ch-2.cpp b/challenge-102/paulo-custodio/cpp/ch-2.cpp
index 24fbf2fb06..4832b1d64c 100644
--- a/challenge-102/paulo-custodio/cpp/ch-2.cpp
+++ b/challenge-102/paulo-custodio/cpp/ch-2.cpp
@@ -49,6 +49,6 @@ int main(int argc, char* argv[]) {
std::cerr << "Usage: ch-1 N" << std::endl;
return EXIT_FAILURE;
}
- else
+ else
std::cout << hash_count(atoi(argv[1])) << std::endl;
}
diff --git a/challenge-102/paulo-custodio/lua/ch-1.lua b/challenge-102/paulo-custodio/lua/ch-1.lua
new file mode 100644
index 0000000000..a24f601c57
--- /dev/null
+++ b/challenge-102/paulo-custodio/lua/ch-1.lua
@@ -0,0 +1,43 @@
+#!/usr/bin/env lua
+
+--[[
+Challenge 102
+
+TASK #1 › Rare Numbers
+Submitted by: Mohammad S Anwar
+
+You are given a positive integer $N.
+
+Write a script to generate all Rare numbers of size $N if exists. Please
+checkout the page for more information about it.
+Examples
+
+(a) 2 digits: 65
+(b) 6 digits: 621770
+(c) 9 digits: 281089082
+--]]
+
+function perfect_square(n)
+ local sq = math.sqrt(n)
+ if math.floor(sq) == sq then
+ return true
+ else
+ return false
+ end
+end
+
+function print_rare(n)
+ for r=10^(n-1),(10^n)-1 do
+ r = math.floor(r) -- convert to int
+ r1 = tonumber(string.reverse(tostring(r)))
+ if perfect_square(r+r1) then
+ if r >= r1 then
+ if perfect_square(r-r1) then
+ io.write(r, "\n")
+ end
+ end
+ end
+ end
+end
+
+print_rare(tonumber(arg[1]))
diff --git a/challenge-102/paulo-custodio/lua/ch-2.lua b/challenge-102/paulo-custodio/lua/ch-2.lua
new file mode 100644
index 0000000000..72d378f496
--- /dev/null
+++ b/challenge-102/paulo-custodio/lua/ch-2.lua
@@ -0,0 +1,46 @@
+#!/usr/bin/env lua
+
+--[[
+Challenge 102
+
+TASK #2 > Hash-counting String
+Submitted by: Stuart Little
+
+You are given a positive integer $N.
+
+Write a script to produce Hash-counting string of that length.
+
+The definition of a hash-counting string is as follows:
+- the string consists only of digits 0-9 and hashes, '#'
+- there are no two consecutive hashes: '##' does not appear in your string
+- the last character is a hash
+- the number immediately preceding each hash (if it exists) is the position
+of that hash in the string, with the position being counted up from 1
+
+It can be shown that for every positive integer N there is exactly one such
+length-N string.
+Examples:
+
+(a) "#" is the counting string of length 1
+(b) "2#" is the counting string of length 2
+(c) "#3#" is the string of length 3
+(d) "#3#5#7#10#" is the string of length 10
+(e) "2#4#6#8#11#14#" is the string of length 14
+--]]
+
+function hash_counting(n)
+ local out, i = '', n
+ while i > 0 do
+ p = i
+ out = '#'..out
+ i = i - 1
+ while i > 0 and p ~= 0 do
+ out = tostring(p % 10)..out
+ i = i - 1
+ p = math.floor(p / 10)
+ end
+ end
+ return out
+end
+
+print(hash_counting(tonumber(arg[1])))
diff --git a/challenge-102/paulo-custodio/perl/ch-1.pl b/challenge-102/paulo-custodio/perl/ch-1.pl
index 587ad59d05..644c5cf065 100644
--- a/challenge-102/paulo-custodio/perl/ch-1.pl
+++ b/challenge-102/paulo-custodio/perl/ch-1.pl
@@ -1,16 +1,16 @@
#!/usr/bin/perl
# Challenge 102
-#
+#
# TASK #1 › Rare Numbers
# Submitted by: Mohammad S Anwar
-#
+#
# You are given a positive integer $N.
-#
-# Write a script to generate all Rare numbers of size $N if exists. Please
+#
+# Write a script to generate all Rare numbers of size $N if exists. Please
# checkout the page for more information about it.
# Examples
-#
+#
# (a) 2 digits: 65
# (b) 6 digits: 621770
# (c) 9 digits: 281089082
@@ -23,21 +23,21 @@ my($N) = @ARGV or die "Usage: ch-1.pl N\n";
print_rare($N);
sub print_rare {
- my($n) = @_;
- for my $r (10**($n-1) .. 10**($n)-1) {
- my $r1=0+(join('', reverse split('', $r)));
- if (perfect_square($r+$r1)) {
- if ($r>=$r1) {
- if (perfect_square($r-$r1)) {
- say $r;
- }
- }
- }
- }
+ my($n) = @_;
+ for my $r (10**($n-1) .. 10**($n)-1) {
+ my $r1 = reverse $r;
+ if (perfect_square($r+$r1)) {
+ if ($r>=$r1) {
+ if (perfect_square($r-$r1)) {
+ say $r;
+ }
+ }
+ }
+ }
}
sub perfect_square {
- my($n) = @_;
- my $x = sqrt($n);
- return ($x == int($x));
+ my($n) = @_;
+ my $x = sqrt($n);
+ return ($x == int($x));
}
diff --git a/challenge-102/paulo-custodio/perl/ch-2.pl b/challenge-102/paulo-custodio/perl/ch-2.pl
index eac91f4044..64afdc45d6 100644
--- a/challenge-102/paulo-custodio/perl/ch-2.pl
+++ b/challenge-102/paulo-custodio/perl/ch-2.pl
@@ -1,25 +1,25 @@
#!/usr/bin/perl
# Challenge 102
-#
+#
# TASK #2 › Hash-counting String
# Submitted by: Stuart Little
-#
+#
# You are given a positive integer $N.
-#
+#
# Write a script to produce Hash-counting string of that length.
-#
+#
# The definition of a hash-counting string is as follows:
# - the string consists only of digits 0-9 and hashes, ‘#’
# - there are no two consecutive hashes: ‘##’ does not appear in your string
# - the last character is a hash
-# - the number immediately preceding each hash (if it exists) is the position
+# - the number immediately preceding each hash (if it exists) is the position
# of that hash in the string, with the position being counted up from 1
-#
-# It can be shown that for every positive integer N there is exactly one such
+#
+# It can be shown that for every positive integer N there is exactly one such
# length-N string.
# Examples:
-#
+#
# (a) "#" is the counting string of length 1
# (b) "2#" is the counting string of length 2
# (c) "#3#" is the string of length 3
@@ -34,15 +34,15 @@ my($N) = @ARGV or die "Usage: ch-1.pl N\n";
say hash_counting($N);
sub hash_counting {
- my($n) = @_;
- my @out;
- for (my $i = $n; $i>0;) {
- my $pos = $i;
- $out[$i--] = '#';
- while ($i>0 && $pos!=0) {
- $out[$i--] = $pos%10;
- $pos = int($pos/10);
- }
- }
- return join('', @out[1..$n]);
+ my($n) = @_;
+ my @out;
+ for (my $i = $n; $i>0;) {
+ my $pos = $i;
+ $out[$i--] = '#';
+ while ($i>0 && $pos!=0) {
+ $out[$i--] = $pos%10;
+ $pos = int($pos/10);
+ }
+ }
+ return join('', @out[1..$n]);
}
diff --git a/challenge-102/paulo-custodio/python/ch-1.py b/challenge-102/paulo-custodio/python/ch-1.py
new file mode 100644
index 0000000000..d513c19117
--- /dev/null
+++ b/challenge-102/paulo-custodio/python/ch-1.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+
+# Challenge 102
+#
+# TASK #1 > Rare Numbers
+# Submitted by: Mohammad S Anwar
+#
+# You are given a positive integer $N.
+#
+# Write a script to generate all Rare numbers of size $N if exists. Please
+# checkout the page for more information about it.
+# Examples
+#
+# (a) 2 digits: 65
+# (b) 6 digits: 621770
+# (c) 9 digits: 281089082
+
+import sys
+import math
+
+def perfect_square(n):
+ sq = math.sqrt(float(n))
+ if math.floor(sq) == sq:
+ return True
+ else:
+ return False
+
+def print_rare(n):
+ for r in range(10**(n-1), 10**n):
+ r1 = int(str(r)[::-1])
+ if perfect_square(r+r1):
+ if r>=r1:
+ if perfect_square(r-r1):
+ print(r)
+
+print_rare(int(sys.argv[1]))
diff --git a/challenge-102/paulo-custodio/python/ch-2.py b/challenge-102/paulo-custodio/python/ch-2.py
new file mode 100644
index 0000000000..558367a422
--- /dev/null
+++ b/challenge-102/paulo-custodio/python/ch-2.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+
+# Challenge 102
+#
+# TASK #2 > Hash-counting String
+# Submitted by: Stuart Little
+#
+# You are given a positive integer $N.
+#
+# Write a script to produce Hash-counting string of that length.
+#
+# The definition of a hash-counting string is as follows:
+# - the string consists only of digits 0-9 and hashes, '#'
+# - there are no two consecutive hashes: '##' does not appear in your string
+# - the last character is a hash
+# - the number immediately preceding each hash (if it exists) is the position
+# of that hash in the string, with the position being counted up from 1
+#
+# It can be shown that for every positive integer N there is exactly one such
+# length-N string.
+# Examples:
+#
+# (a) "#" is the counting string of length 1
+# (b) "2#" is the counting string of length 2
+# (c) "#3#" is the string of length 3
+# (d) "#3#5#7#10#" is the string of length 10
+# (e) "2#4#6#8#11#14#" is the string of length 14
+
+import sys
+
+def hash_counting(n):
+ out = ''
+ i = n
+ while i>0:
+ p = i
+ out = '#'+out
+ i -= 1
+ while i>0 and p!=0:
+ out = str(p % 10)+out
+ i -= 1
+ p = int(p/10)
+ return out
+
+print(hash_counting(int(sys.argv[1])))
diff --git a/challenge-102/yet-ebreo/perl/ch-2.pl b/challenge-102/yet-ebreo/perl/ch-2.pl
new file mode 100644
index 0000000000..4197f1d406
--- /dev/null
+++ b/challenge-102/yet-ebreo/perl/ch-2.pl
@@ -0,0 +1,37 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use feature qw(say);
+
+
+# You are given a positive integer $N.
+
+# Write a script to produce Hash-counting string of that length.
+
+# The definition of a hash-counting string is as follows:
+
+# - the string consists only of digits 0-9 and hashes, ‘#’
+# - there are no two consecutive hashes: ‘##’ does not appear in your string
+# - the last character is a hash
+# - the number immediately preceding each hash (if it exists) is the position of that hash in the string, with the position being counted up from 1
+# It can be shown that for every positive integer N there is exactly one such length-N string.
+
+# Examples:
+# (a) "#" is the counting string of length 1
+# (b) "2#" is the counting string of length 2
+# (c) "#3#" is the string of length 3
+# (d) "#3#5#7#10#" is the string of length 10
+# (e) "2#4#6#8#11#14#" is the string of length 14
+
+my $N = $ARGV[0] || 2;
+my $out = "";
+
+while ($N) {
+ $out = ($N>1?"$N":"")."#$out";
+ $N = $ARGV[0] - length $out;
+}
+
+
+say $out;
+
generated by cgit (git 2.34.1) at 2026-07-03 23:36:59 +0000