- Added solutions by Arne Sommer.

- Added blog post by James Smith.
- Added solutions by Bob Lied.
- Added solutions by Dave Jacoby.
- Added solutions by E. Choroba.
- Added solutions by Ali Moradi.
- Added solutions by Marton Polgar.
- Added solutions by Luca Ferrari.
- Added solutions by Pip Stuart.
- Added solutions by Peter Campbell Smith.
- Added solutions by Robbie Hatley.
- Added solutions by Stephen G. Lynn.
- Added solutions by Rawley Fowler.

10 files changed, 83 insertions, 2 deletions

diff --git a/challenge-198/eric-cheung/python/ch-1.py b/challenge-198/eric-cheung/python/ch-1.py
new file mode 100755
index 0000000000..34d0347180
--- /dev/null
+++ b/challenge-198/eric-cheung/python/ch-1.py
@@ -0,0 +1,12 @@
+

+arrInputList = [2, 5, 8, 1]  ## Example 1

+## arrInputList = [3]  ## Example 2

+

+arrInputList.sort()

+arrDiff = [arrInputList[nIndx + 1] - arrInputList[nIndx] for nIndx in range(0, len(arrInputList) - 1)]

+

+if len(arrDiff) > 0:

+    nMaxArrDiff = max(arrDiff)

+    print (arrDiff.count(nMaxArrDiff))

+else:

+    print (0)

diff --git a/challenge-198/eric-cheung/python/ch-2.py b/challenge-198/eric-cheung/python/ch-2.py
new file mode 100755
index 0000000000..315da4e457
--- /dev/null
+++ b/challenge-198/eric-cheung/python/ch-2.py
@@ -0,0 +1,11 @@
+

+from sympy import isprime

+

+## nInput = 10  ## Example 1

+## nInput = 15  ## Example 2

+## nInput = 1  ## Example 3

+nInput = 25  ## Example 4

+

+arrPrime = [nLoop for nLoop in range(2, nInput) if isprime(nLoop)]

+

+print (len(arrPrime))

diff --git a/challenge-198/laurent-rosenfeld/blog.txt b/challenge-198/laurent-rosenfeld/blog.txt
new file mode 100644
index 0000000000..792185b39e
--- /dev/null
+++ b/challenge-198/laurent-rosenfeld/blog.txt
@@ -0,0 +1 @@
+https://blogs.perl.org/users/laurent_r/2023/01/perl-weekly-challenge-198-max-gap-and-prime-count.html
diff --git a/challenge-198/laurent-rosenfeld/perl/ch-1.pl b/challenge-198/laurent-rosenfeld/perl/ch-1.pl
new file mode 100644
index 0000000000..b99e96ef36
--- /dev/null
+++ b/challenge-198/laurent-rosenfeld/perl/ch-1.pl
@@ -0,0 +1,20 @@
+use strict;
+use warnings;
+use feature qw/say/;
+
+sub max_gap  {
+    return 0 if scalar @_ < 2;
+    my @sorted = sort { $a <=> $b } @_;
+    my %gaps;
+    for my $i (1..$#sorted) {
+        push @{$gaps{$sorted[$i] - $sorted[$i-1]}}, $i;
+    }
+    my $max_gap = 0;
+    for my $k (keys %gaps) {
+        $max_gap = $k if $k > $max_gap;
+    }
+    return scalar @{$gaps{$max_gap}};
+}
+for my $test ([<2 5 8 1>], [<2 7>], [3,], [<12 2 6 5 15 9>]) {
+    printf "%-20s => %d\n", "@$test", max_gap @$test;
+}
diff --git a/challenge-198/laurent-rosenfeld/perl/ch-2.pl b/challenge-198/laurent-rosenfeld/perl/ch-2.pl
new file mode 100644
index 0000000000..d0903cf706
--- /dev/null
+++ b/challenge-198/laurent-rosenfeld/perl/ch-2.pl
@@ -0,0 +1,18 @@
+use strict;
+use warnings;
+use feature qw/say/;
+
+sub is_prime {
+    my $num = shift;
+    for my $i (2 .. $num ** .5) {
+        return 0 if $num % $i == 0;
+    }
+    return 1;
+}
+sub count_primes {
+    my $n = shift;
+    return scalar grep is_prime($_), 2..$n;
+}
+for my $i (<10 15 1 25>) {
+    say "$i \t => ", count_primes $i;
+}
diff --git a/challenge-198/laurent-rosenfeld/raku/ch-1.raku b/challenge-198/laurent-rosenfeld/raku/ch-1.raku
new file mode 100644
index 0000000000..c7a6fef8e5
--- /dev/null
+++ b/challenge-198/laurent-rosenfeld/raku/ch-1.raku
@@ -0,0 +1,13 @@
+sub max-gap (@in) {
+    return 0 if @in.elems < 2;
+    my @sorted = sort @in;
+    my %gaps;
+    for 1..@sorted.end -> $i {
+        push %gaps, ( @sorted[$i] - @sorted[$i-1] => $i );
+    }
+    my $max-gap = %gaps.keys.max;
+    return %gaps{$max-gap}.elems;
+}
+for <2 5 8 1>, <2 7>, (3,), <12 2 6 5 15 9> -> @test {
+    say (~@test).fmt("%-20s => "), max-gap @test;
+}
diff --git a/challenge-198/laurent-rosenfeld/raku/ch-2.raku b/challenge-198/laurent-rosenfeld/raku/ch-2.raku
new file mode 100644
index 0000000000..91128040f7
--- /dev/null
+++ b/challenge-198/laurent-rosenfeld/raku/ch-2.raku
@@ -0,0 +1,6 @@
+sub count-primes (Int $n) {
+    return (grep ({.is-prime}), 1..$n).elems;
+}
+for <10 15 1 25> -> $i {
+    say "$i \t => ", count-primes $i;
+}
diff --git a/challenge-198/rawleyfowler/README.md b/challenge-198/rawleyfowler/README.md
index f55ad6c829..4d4b3f88f8 100644
--- a/challenge-198/rawleyfowler/README.md
+++ b/challenge-198/rawleyfowler/README.md
@@ -1,5 +1,5 @@
 ## How to run
 ```bash
-raku task1.raku '2 5 8 1' # Find gap pairs
-raku task2.raku '100'     # Find primes
+raku raku/ch-1.raku '2 5 8 1' # Find gap pairs
+raku raku/ch-2.raku '100'     # Find primes
 ```
diff --git a/challenge-198/rawleyfowler/task1.raku b/challenge-198/rawleyfowler/raku/ch-1.raku
index e3f2468cec..e3f2468cec 100644
--- a/challenge-198/rawleyfowler/task1.raku
+++ b/challenge-198/rawleyfowler/raku/ch-1.raku
diff --git a/challenge-198/rawleyfowler/task2.raku b/challenge-198/rawleyfowler/raku/ch-2.raku
index b7116610e4..b7116610e4 100644
--- a/challenge-198/rawleyfowler/task2.raku
+++ b/challenge-198/rawleyfowler/raku/ch-2.raku