From b61107f1bb11bbca80bbda7c0f9a63221eec1bbe Mon Sep 17 00:00:00 2001
From: Dave Jacoby <jacoby.david@gmail.com>
Date: Mon, 28 Jun 2021 15:58:12 -0400
Subject: All but Blogging

---
 challenge-119/dave-jacoby/node/ch-1.js | 23 +++++++++++++++
 challenge-119/dave-jacoby/node/ch-2.js | 51 ++++++++++++++++++++++++++++++++
 challenge-119/dave-jacoby/perl/ch-1.pl | 24 +++++++++++++++
 challenge-119/dave-jacoby/perl/ch-2.pl | 54 ++++++++++++++++++++++++++++++++++
 4 files changed, 152 insertions(+)
 create mode 100644 challenge-119/dave-jacoby/node/ch-1.js
 create mode 100644 challenge-119/dave-jacoby/node/ch-2.js
 create mode 100644 challenge-119/dave-jacoby/perl/ch-1.pl
 create mode 100644 challenge-119/dave-jacoby/perl/ch-2.pl

diff --git a/challenge-119/dave-jacoby/node/ch-1.js b/challenge-119/dave-jacoby/node/ch-1.js
new file mode 100644
index 0000000000..6d1075d34d
--- /dev/null
+++ b/challenge-119/dave-jacoby/node/ch-1.js
@@ -0,0 +1,23 @@
+"use strict";
+
+for (let i in Array(21).fill("")) {
+  let v = flopped(i);
+  console.log(["", i, v].join("\t"));
+}
+
+console.log(["", 86, flopped(86)].join("\t"));
+console.log(["", 101, flopped(101)].join("\t"));
+console.log(["", 18, flopped(18)].join("\t"));
+console.log(["", 33, flopped(33)].join("\t"));
+
+function flopped(n) {
+  let b = parseInt(n).toString(2);
+  while (b.length < 8) {
+    b = "0" + b;
+  }
+  let front = b.substring(0, 4);
+  let back = b.substring(4);
+  let r = back + front;
+  let x = parseInt(r, 2);
+  return x;
+}
diff --git a/challenge-119/dave-jacoby/node/ch-2.js b/challenge-119/dave-jacoby/node/ch-2.js
new file mode 100644
index 0000000000..7386e2a0db
--- /dev/null
+++ b/challenge-119/dave-jacoby/node/ch-2.js
@@ -0,0 +1,51 @@
+"use strict";
+
+// let list = Array(20).fill();
+// for (let i in list) {
+//   let j = first_pass(i);
+//   let s = get_sequence(i * 2);
+//   let v = solve_sequence(i);
+//   console.log(["", "i", i, "j", j, "v", v].join("\t"));
+// }
+
+let list = [2, 5, 10, 60, 200];
+
+for (let i in list) {
+  let n = list[i];
+  let s = solve_sequence(n);
+  console.log(["", n, s].join("\t"));
+}
+
+function solve_sequence(n) {
+  let j = n * 2;
+  let s = get_sequence(1 + j);
+  while (s[n] == undefined) {
+    j = j * 2;
+    s = get_sequence(j);
+  }
+  return s[n];
+}
+
+function get_sequence(n) {
+  n = parseInt(n);
+  let sequence = Array(n)
+    .fill("")
+    .map((x, i) => first_pass(i + 1))
+    .filter((x) => !x.toString().match(/0/))
+    .filter((x) => !x.toString().match(/11/));
+  sequence.unshift(0);
+  return sequence;
+}
+
+function first_pass(n) {
+  if (n == 0) {
+    return 0;
+  }
+  let output = [];
+  while (n) {
+    let i = n % 4;
+    n = parseInt(n / 4);
+    output.push(i);
+  }
+  return output.reverse().join("");
+}
diff --git a/challenge-119/dave-jacoby/perl/ch-1.pl b/challenge-119/dave-jacoby/perl/ch-1.pl
new file mode 100644
index 0000000000..08672aa798
--- /dev/null
+++ b/challenge-119/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,24 @@
+#!/usr/bin/env perl
+
+use feature qw{say state signatures};
+use strict;
+use warnings;
+use utf8;
+no warnings qw{ experimental };
+
+for my $n ( 0 .. 20 ) {
+    say join "\t", '', $n, flopped($n);
+}
+
+    say join "\t", '', 86, flopped(86);
+    say join "\t", '', 101, flopped(101);
+    say join "\t", '', 18, flopped(18);
+    say join "\t", '', 33, flopped(33);
+
+sub flopped ($n) {
+    my $b = sprintf '%08b', $n;
+    my $c = join '', substr( $b, 4, 4 ), substr( $b, 0, 4 );
+    my $r = oct( '0b' . $c );
+    return $r;
+}
+
diff --git a/challenge-119/dave-jacoby/perl/ch-2.pl b/challenge-119/dave-jacoby/perl/ch-2.pl
new file mode 100644
index 0000000000..702ef4b13a
--- /dev/null
+++ b/challenge-119/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,54 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw{ postderef say signatures state };
+no warnings qw{ experimental };
+
+use Memoize;
+memoize('first_pass');
+
+my @list = map { int } @ARGV;
+@list = ( 2, 5, 10, 60, 200 ) unless scalar @list;
+
+for my $n (@list) {
+    say join "\t", '', $n, solve_sequence($n);
+}
+
+# here we get an array such that index $n is in the array
+# using increasingly aggressive methods, then 
+sub solve_sequence( $n ) {
+    my $j        = $n * 2;
+    my @sequence = get_sequence( 1 .. $j );
+    while ( !$sequence[$n] ) {
+        $j        = $j * 2;
+        @sequence = get_sequence( 1 .. $j );
+    }
+    return $sequence[$n];
+}
+
+# the next things we want to do are to remove the blocked numbers
+# which contain either 0 or 11, and then add another entry to the
+# start of the array so that 1 aligns with 1.
+sub get_sequence( @arr ) {
+    my @seq =
+        grep { !/11/ }
+        grep { !/0/ }
+        map  { first_pass($_) } @arr;
+    unshift @seq, '';
+    return @seq;
+}
+
+# the numbers will contain only the digits 1, 2 and 3, so to limit 
+# the amount of numbers we have to come up with, I first make everything
+# base 4. This function is memoizable and so I memoized it.
+sub first_pass ( $n ) {
+    return $n if $n == 0;
+    my @output;
+    while ($n) {
+        my $i = $n % 4;
+        $n = int $n / 4;
+        push @output, $i;
+    }
+    return join '', reverse @output;
+}
-- 
cgit