Merge pull request #5368 from Firedrake/rogerbw-challenge-143

Solutions for challenge #143

12 files changed, 661 insertions, 0 deletions

diff --git a/challenge-143/roger-bell-west/kotlin/ch-2.kt b/challenge-143/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..8a57e98251
--- /dev/null
+++ b/challenge-143/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,53 @@
+fun factorpairs(n: Int): ArrayList<Int> {
+  if (n == 1) {
+    return ArrayList(2)
+  }
+  var ff=ArrayList<Int>()
+  var s=Math.sqrt(n.toDouble()).toInt()
+  if (s*s == n) {
+    ff.add(s*2)
+    s--
+  }
+  for (pf in 2..s) {
+    if (n % pf == 0) {
+      ff.add(pf+n/pf)
+    }
+  }
+  ff.add(n+1)
+  return ff
+}
+
+fun is_stealthy(n: Int): Boolean {
+  val p=factorpairs(n)
+  if (p.count() == 1) {
+    return false
+  }
+  for (ix in 0..p.count()-2) {
+    for (iy in ix+1..p.count()-1) {
+      if (Math.abs(p[ix]-p[iy])==1) {
+        return true
+      }
+    }
+  }
+  return false
+}
+
+fun main() {
+  if (is_stealthy(36)) {
+    print("Pass")
+  } else {
+    print("FAIL")
+  }
+  print(" ")
+  if (is_stealthy(12)) {
+    print("Pass")
+  } else {
+    print("FAIL")
+  }
+  print(" ")
+  if (!is_stealthy(6)) {
+    println("Pass")
+  } else {
+    println("FAIL")
+  }
+}
diff --git a/challenge-143/roger-bell-west/perl/ch-1.pl b/challenge-143/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..78f8966e91
--- /dev/null
+++ b/challenge-143/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,58 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+use Test::More tests => 3;
+
+is(exval("10 + 20 - 5"),25,'example 1');
+is(exval("(10 + 20 - 5) * 2"),50,'example 2');
+is(exval("10 + 20 - 5 * 2"),20,'example 3');
+
+sub exval {
+  my $expr=shift;
+  my @op=("(",")","+","-","*");
+  my %opp=map {$op[$_] => $_} (0..$#op);
+  my @re=("-?[0-9]+");
+  foreach my $op (@op) {
+    push @re,quotemeta($op);
+  }
+  my $re='('.join('|',@re).')';
+  my @opstack;
+  my @valstack;
+  foreach my $token ($expr =~ /$re/g) {
+    if ($token =~ /^-?[0-9]+$/) {
+      push @valstack,0+$token;
+    } elsif ($token eq '(') {
+      push @opstack,$token;
+    } elsif ($token eq ')') {
+      while ($opstack[-1] ne '(') {
+        push @valstack,operate(pop @opstack,pop @valstack,pop @valstack);
+      }
+      pop @opstack;
+    } elsif (exists $opp{$token}) {
+      while (scalar @opstack > 0 && $opp{$opstack[-1]} >= $opp{$token}) {
+        push @valstack,operate(pop @opstack,pop @valstack,pop @valstack);
+      }
+      push @opstack,$token;
+    } else {
+      die "bad token $token\n";
+    }
+  }
+  while (scalar @opstack > 0) {
+    push @valstack,operate(pop @opstack,pop @valstack,pop @valstack);
+  }
+  return $valstack[0];
+}
+
+sub operate {
+  my ($op,$a,$b)=@_;
+  if ($op eq '+') {
+    return $b+$a;
+  } elsif ($op eq '-') {
+    return $b-$a;
+  } elsif ($op eq '*') {
+    return $b*$a;
+  }
+  die "unknown operator $op\n";
+}
diff --git a/challenge-143/roger-bell-west/perl/ch-2.pl b/challenge-143/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..3fbc9bcef6
--- /dev/null
+++ b/challenge-143/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,46 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+use Test::More tests => 3;
+
+is(is_stealthy(36),1,'example 1');
+is(is_stealthy(12),1,'example 2');
+is(is_stealthy(6),0,'example 3');
+
+sub factorpairs {
+  my $n=shift;
+  if ($n==1) {
+    return [2];
+  }
+  my @ff;
+  my $s=int(sqrt($n));
+  if ($s*$s == $n) {
+    push @ff,$s*2;
+    $s--;
+  }
+  foreach my $pf (2..$s) {
+    if ($n % $pf == 0) {
+      push @ff,$pf+$n/$pf;
+    }
+  }
+  push @ff,1+$n;
+  return \@ff;
+}
+
+sub is_stealthy {
+  my $n=shift;
+  my $p=factorpairs($n);
+  if (scalar @{$p}==1) {
+    return 0;
+  }
+  foreach my $ix (0..scalar @{$p}-2) {
+    foreach my $iy ($ix+1..scalar @{$p}-1) {
+      if (abs($p->[$ix]-$p->[$iy])==1) {
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
diff --git a/challenge-143/roger-bell-west/postscript/ch-2.ps b/challenge-143/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..e1cdbab9b3
--- /dev/null
+++ b/challenge-143/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,55 @@
+%!PS
+
+/apush { % [a b] c -> [a b c]
+    /t exch def
+    [ exch aload pop t ]
+} bind def
+
+/factorpairs {
+    /nn exch def
+    nn 1 eq {
+        [ 2 ]
+    } {
+        /ff 0 array def
+        /s nn sqrt cvi def
+        s s mul nn eq {
+            /ff ff s 2 mul apush def
+            /s s 1 sub def
+        } if
+        2 1 s {
+            /pf exch def
+            nn pf mod 0 eq {
+                /ff ff pf nn pf idiv add apush def
+            } if
+        } for
+        /ff ff 1 nn add apush def
+        ff
+    } ifelse
+} bind def
+
+/is_stealthy {
+    /n exch def
+    /p n factorpairs def
+    /stl false def
+    p length 1 ne {
+        0 1 p length 2 sub {
+            /ix exch def
+            ix 1 add 1 p length 1 sub {
+                /iy exch def
+                p ix get p iy get sub abs
+                1 eq {
+                    /stl true def
+                    exit
+                } if
+            } for
+            stl {
+                exit
+            } if
+        } for
+    } if
+    stl
+} bind def
+
+36 is_stealthy true eq { (Pass) } { (FAIL) } ifelse print ( ) print
+12 is_stealthy true eq { (Pass) } { (FAIL) } ifelse print ( ) print
+6 is_stealthy false eq { (Pass) } { (FAIL) } ifelse =
diff --git a/challenge-143/roger-bell-west/python/ch-1.py b/challenge-143/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..2fa9707527
--- /dev/null
+++ b/challenge-143/roger-bell-west/python/ch-1.py
@@ -0,0 +1,57 @@
+#! /usr/bin/python3
+
+import unittest
+
+import re
+
+def operate(op,a,b):
+  if op == "+":
+    return b+a
+  elif op == "-":
+    return b-a
+  elif op == "*":
+    return b*a
+  print("unknown operator")
+
+def exval(expr):
+  op=["(",")","+","-","*"]
+  opp=dict()
+  rec=[r"-?[0-9]+"]
+  for i,o in enumerate(op):
+    opp[o]=i
+    rec.append("\\" + o)
+  ret=re.compile("(" + "|".join(rec) + ")")
+  ren=re.compile("^" + rec[0] + "$")
+  opstack=[]
+  valstack=[]
+  for token in ret.findall(expr):
+    if ren.match(token):
+      valstack.append(int(token))
+    elif token == "(":
+      opstack.append(token)
+    elif token == ")":
+      while opstack[-1] != "(":
+        valstack.append(operate(opstack.pop(),valstack.pop(),valstack.pop()))
+      opstack.pop()
+    elif token in opp:
+      while len(opstack)>0 and opp[opstack[-1]] >= opp[token]:
+        valstack.append(operate(opstack.pop(),valstack.pop(),valstack.pop()))
+      opstack.append(token)
+    else:
+      print("bad token")
+  while len(opstack)>0:
+    valstack.append(operate(opstack.pop(),valstack.pop(),valstack.pop()))
+  return valstack[0]
+
+class TestExval(unittest.TestCase):
+
+        def test_ex1(self):
+          self.assertEqual(exval("10 + 20 - 5"),25,'example 1')
+
+        def test_ex2(self):
+          self.assertEqual(exval("(10 + 20 - 5) * 2"),50,'example 2')
+
+        def test_ex3(self):
+          self.assertEqual(exval("10 + 20 - 5 * 2"),20,'example 3')
+
+unittest.main()
diff --git a/challenge-143/roger-bell-west/python/ch-2.py b/challenge-143/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..443f52df23
--- /dev/null
+++ b/challenge-143/roger-bell-west/python/ch-2.py
@@ -0,0 +1,42 @@
+#! /usr/bin/python3
+
+import unittest
+
+from math import sqrt
+
+def factorpairs(n):
+  if n==1:
+    return [2]
+  ff=[]
+  s=int(sqrt(n))
+  if s*s==n:
+    ff.append(s*2)
+    s-=1
+  for pf in range(2,s+1):
+    if n % pf == 0:
+      ff.append(pf+int(n/pf))
+  ff.append(n+1)
+  return ff
+
+def is_stealthy(n):
+  p=factorpairs(n)
+  if len(p)==1:
+    return False
+  for ix in range(len(p)-1):
+    for iy in range(ix+1,len(p)):
+      if abs(p[ix]-p[iy])==1:
+        return True
+  return False
+
+class TestIs_Stealthy(unittest.TestCase):
+
+        def test_ex1(self):
+          self.assertEqual(is_stealthy(36),True,'example 1')
+
+        def test_ex2(self):
+          self.assertEqual(is_stealthy(12),True,'example 2')
+
+        def test_ex3(self):
+          self.assertEqual(is_stealthy(6),False,'example 3')
+
+unittest.main()
diff --git a/challenge-143/roger-bell-west/raku/ch-1.p6 b/challenge-143/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..b3c6465031
--- /dev/null
+++ b/challenge-143/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,54 @@
+#! /usr/bin/perl6
+
+use Test;
+plan 3;
+
+is(exval("10 + 20 - 5"),25,'example 1');
+is(exval("(10 + 20 - 5) * 2"),50,'example 2');
+is(exval("10 + 20 - 5 * 2"),20,'example 3');
+
+sub exval($expr) {
+  my @op=("(",")","+","-","*");
+  my %opp=map {@op[$_] => $_},(0..@op.end);
+  my @re=("\\-? <[0..9]>+");
+  for @op -> $op {
+    @re.push('\\' ~ $op);
+  }
+  my $re='(' ~ join('|',@re) ~ ')';
+  my @opstack;
+  my @valstack;
+  for ($expr ~~ m:g/<$re>/) -> $token {
+    if ($token ~~ /^ '-'? <[0..9]>+ /) {
+      push @valstack,0+$token;
+    } elsif ($token eq '(') {
+      push @opstack,$token;
+    } elsif ($token eq ')') {
+      while (@opstack[*-1] ne '(') {
+        push @valstack,operate(@opstack.pop,@valstack.pop,@valstack.pop);
+      }
+      pop @opstack;
+    } elsif (%opp{$token}:exists) {
+      while (@opstack.elems > 0 && %opp{@opstack[*-1]} >= %opp{$token}) {
+        push @valstack,operate(@opstack.pop,@valstack.pop,@valstack.pop);
+      }
+      push @opstack,$token;
+     } else {
+       die "bad token $token\n";
+     }
+  }
+  while (@opstack.elems > 0) {
+    push @valstack,operate(@opstack.pop,@valstack.pop,@valstack.pop);
+  }
+  return @valstack[0];
+}
+
+sub operate($op,$a,$b) {
+  if ($op eq '+') {
+    return $b+$a;
+  } elsif ($op eq '-') {
+    return $b-$a;
+  } elsif ($op eq '*') {
+    return $b*$a;
+  }
+  die "unknown operator $op\n";
+}
diff --git a/challenge-143/roger-bell-west/raku/ch-2.p6 b/challenge-143/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..4047fd9d52
--- /dev/null
+++ b/challenge-143/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,42 @@
+#! /usr/bin/perl6
+
+use Test;
+plan 3;
+
+is(is_stealthy(36),True,'example 1');
+is(is_stealthy(12),True,'example 2');
+is(is_stealthy(6),False,'example 3');
+
+sub factorpairs($n) {
+  if ($n==1) {
+    return [2];
+  }
+  my @ff;
+  my $s=floor(sqrt($n));
+  if ($s*$s == $n) {
+    push @ff,$s*2;
+    $s--;
+  }
+  for (2..$s) -> $pf {
+    if ($n % $pf == 0) {
+      push @ff,$pf+($n div $pf);
+    }
+  }
+  push @ff,1+$n;
+  return @ff;
+}
+
+sub is_stealthy($n) {
+  my @p=factorpairs($n);
+  if (@p.elems==1) {
+    return False;
+  }
+  for (0..@p.end-1) -> $ix {
+    for ($ix+1..@p.end) -> $iy {
+      if (abs(@p[$ix]-@p[$iy])==1) {
+        return True;
+      }
+    }
+  }
+  return False;
+}
diff --git a/challenge-143/roger-bell-west/ruby/ch-1.rb b/challenge-143/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..0b54123208
--- /dev/null
+++ b/challenge-143/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,67 @@
+#! /usr/bin/ruby
+
+def operate(op,a,b)
+  if op=="+" then
+    return b+a
+  elsif op=="-" then
+    return b-a
+  elsif op=="*" then
+    return b*a
+  end
+end
+
+def exval(expr)
+  op=["(",")","+","-","*"]
+  opp=Hash.new
+  rec=["-?[0-9]+"]
+  op.each_with_index do |o,i|
+    opp[o]=i
+    rec.push('\\' + o)
+  end
+  ret=Regexp.new("(" + rec.join("|") + ")")
+  ren=Regexp.new("^" + rec[0] + "$")
+  opstack=[]
+  valstack=[]
+  expr.scan(ret).each do |ta|
+    token=ta[0]
+    if token.match(ren) then
+      valstack.push(token.to_i())
+    elsif token == "(" then
+      opstack.push(token)
+    elsif token == ")" then
+      while opstack[-1] != "(" do
+        valstack.push(operate(opstack.pop(),valstack.pop(),valstack.pop()))
+      end
+      opstack.pop()
+    elsif opp.has_key?(token) then
+      while opstack.length>0 && opp[opstack[-1]] >= opp[token] do
+        valstack.push(operate(opstack.pop(),valstack.pop(),valstack.pop()))
+      end
+      opstack.push(token)
+    else
+      print("bad token")
+    end
+  end
+  while opstack.length>0 do
+    valstack.push(operate(opstack.pop(),valstack.pop(),valstack.pop()))
+  end
+  return valstack[0]
+end
+
+require 'test/unit'
+
+class TestExval < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(25,exval("10 + 20 - 5"))
+  end
+
+  def test_ex2
+    assert_equal(50,exval("(10 + 20 - 5) * 2"))
+  end
+
+  def test_ex3
+    assert_equal(20,exval("10 + 20 - 5 * 2"))
+  end
+
+end
diff --git a/challenge-143/roger-bell-west/ruby/ch-2.rb b/challenge-143/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..552bdd2a8c
--- /dev/null
+++ b/challenge-143/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,53 @@
+#! /usr/bin/ruby
+
+def factorpairs(n)
+  if n==1 then
+    return [2]
+  end
+  ff=[]
+  s=Math.sqrt(n).floor
+  if s*s==n then
+    ff.push(s*2)
+    s-=1
+  end
+  2.upto(s) do |pf|
+    if n % pf == 0 then
+      ff.push(n/pf+pf)
+    end
+  end
+  ff.push(1+n)
+  return ff
+end
+
+def is_stealthy(n)
+  p=factorpairs(n)
+  if p.length()==1 then
+    return false
+  end
+  0.upto(p.length()-2) do |ix|
+    ix.upto(p.length()-1) do |iy|
+      if (p[ix]-p[iy]).abs==1 then
+        return true
+      end
+    end
+  end
+  return false
+end
+
+require 'test/unit'
+
+class TestIs_Stealthy < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(true,is_stealthy(36))
+  end
+
+  def test_ex2
+    assert_equal(true,is_stealthy(12))
+  end
+
+  def test_ex3
+    assert_equal(false,is_stealthy(6))
+  end
+
+end
diff --git a/challenge-143/roger-bell-west/rust/ch-1.rs b/challenge-143/roger-bell-west/rust/ch-1.rs
new file mode 100644
index 0000000000..91f3b08a5e
--- /dev/null
+++ b/challenge-143/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,82 @@
+use regex::Regex;
+use std::collections::HashMap;
+
+#[test]
+fn test_ex1() {
+    assert_eq!(exval("10 + 20 - 5"), 25);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(exval("(10 + 20 - 5) * 2"), 50);
+}
+
+#[test]
+fn test_ex3() {
+    assert_eq!(exval("10 + 20 - 5 * 2"), 20);
+}
+
+fn operate(op: char, a: i32, b: i32) -> i32 {
+    if op == '+' {
+        return b + a;
+    } else if op == '-' {
+        return b - a;
+    } else if op == '*' {
+        return b * a;
+    }
+    println!("Invalid operator {}", op);
+    0
+}
+
+fn exval(expr: &str) -> i32 {
+    let op = ['(', ')', '+', '-', '*'];
+    let mut opp: HashMap<char, usize> = HashMap::new();
+    let mut rec = vec!["-?[0-9]+".to_string()];
+    for (i, o) in op.iter().enumerate() {
+        opp.insert(*o, i);
+        let ss = "\\".to_string() + &o.to_string();
+        rec.push(ss);
+    }
+    let ret =
+        Regex::new(&("(".to_string() + &rec.join("|") + &")".to_string()))
+            .unwrap();
+    let ren =
+        Regex::new(&("^".to_string() + &rec[0] + &"$".to_string())).unwrap();
+    let mut opstack: Vec<char> = vec![];
+    let mut valstack: Vec<i32> = vec![];
+    for tm in ret.find_iter(expr) {
+        let token = tm.as_str();
+        let tokchar = token.chars().nth(0).unwrap();
+        if ren.is_match(token) {
+            valstack.push(token.parse::<i32>().unwrap());
+            println!("{:?}", valstack);
+        } else if token == "(" {
+            opstack.push('(');
+        } else if token == ")" {
+            while opstack[opstack.len() - 1] != '(' {
+                let a=valstack.pop().unwrap();
+                let b=valstack.pop().unwrap();
+                valstack.push(operate(opstack.pop().unwrap(),a,b));
+            }
+            opstack.pop().unwrap();
+        } else if opp.contains_key(&tokchar) {
+            while opstack.len() > 0
+                && opp.get(&opstack[opstack.len() - 1]).unwrap()
+                    >= opp.get(&tokchar).unwrap()
+            {
+                let a=valstack.pop().unwrap();
+                let b=valstack.pop().unwrap();
+                valstack.push(operate(opstack.pop().unwrap(),a,b));
+            }
+            opstack.push(tokchar);
+        } else {
+            println!("Bad token");
+        }
+    }
+    while opstack.len() > 0 {
+                let a=valstack.pop().unwrap();
+                let b=valstack.pop().unwrap();
+                valstack.push(operate(opstack.pop().unwrap(),a,b));
+    }
+    valstack[0]
+}
diff --git a/challenge-143/roger-bell-west/rust/ch-2.rs b/challenge-143/roger-bell-west/rust/ch-2.rs
new file mode 100755
index 0000000000..74de3e1044
--- /dev/null
+++ b/challenge-143/roger-bell-west/rust/ch-2.rs
@@ -0,0 +1,52 @@
+#! /bin/sh
+//usr/bin/env rustc --test $0 -o ${0}x && ./${0}x; rm -f ${0}x ; exit
+
+#[test]
+fn test_ex1() {
+    assert_eq!(is_stealthy(36), true);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(is_stealthy(12), true);
+}
+
+#[test]
+fn test_ex3() {
+    assert_eq!(is_stealthy(6), false);
+}
+
+fn factorpairs(n: i32) -> Vec<i32> {
+    let mut ff = vec![];
+    if n == 1 {
+        ff.push(2);
+        return ff;
+    }
+    let mut s = (n as f64).sqrt() as i32;
+    if s * s == n {
+        ff.push(s * 2);
+        s -= 1;
+    }
+    for pf in 2..=s {
+        if n % pf == 0 {
+            ff.push(pf + n / pf);
+        }
+    }
+    ff.push(1 + n);
+    ff
+}
+
+fn is_stealthy(n: i32) -> bool {
+    let p = factorpairs(n);
+    if p.len() == 1 {
+        return false;
+    }
+    for ix in 0..p.len() - 1 {
+        for iy in ix + 1..p.len() {
+            if (p[ix] - p[iy]).abs() == 1 {
+                return true;
+            }
+        }
+    }
+    false
+}