From 9f46b534e91523b79e118245ae6f6af76dccb81c Mon Sep 17 00:00:00 2001
From: Eric Mertens <emertens@galois.com>
Date: Tue, 15 Apr 2008 01:00:37 -0700
Subject: [PATCH 1/2] export <blum-blum-shub> in random.blum-blum-shub

---
 extra/project-euler/164/164.factor                |  2 +-
 extra/random/blum-blum-shub/blum-blum-shub.factor | 11 +++++------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/extra/project-euler/164/164.factor b/extra/project-euler/164/164.factor
index 67397593bd..bf1f5dcf9b 100644
--- a/extra/project-euler/164/164.factor
+++ b/extra/project-euler/164/164.factor
@@ -30,4 +30,4 @@ IN: project-euler.164
 PRIVATE>
 
 : euler164 ( -- n )
-    init-table 19 [ next-table ] times values sum ;
\ No newline at end of file
+    init-table 19 [ next-table ] times values sum ;
diff --git a/extra/random/blum-blum-shub/blum-blum-shub.factor b/extra/random/blum-blum-shub/blum-blum-shub.factor
index db8fe540e5..e60990075c 100755
--- a/extra/random/blum-blum-shub/blum-blum-shub.factor
+++ b/extra/random/blum-blum-shub/blum-blum-shub.factor
@@ -12,17 +12,16 @@ TUPLE: blum-blum-shub x n ;
 : generate-bbs-primes ( numbits -- p q )
     [ [ random-prime ] curry [ 4 mod 3 = ] generate ] dup bi ;
 
+: next-bbs-bit ( bbs -- bit )
+    [ [ x>> 2 ] [ n>> ] bi ^mod dup ] keep (>>x) 1 bitand ;
+
+PRIVATE>
+
 : <blum-blum-shub> ( numbits -- blum-blum-shub )
     generate-bbs-primes *
     [ find-relative-prime ] keep
     blum-blum-shub boa ;
 
-: next-bbs-bit ( bbs -- bit )
-    [ [ x>> 2 ] [ n>> ] bi ^mod ] keep
-    over >>x drop 1 bitand ;
-
-PRIVATE>
-
 M: blum-blum-shub random-32* ( bbs -- r )
     0 32 rot
     [ next-bbs-bit swap 1 shift bitor ] curry times ;

From 8d0fdd365128dc62da34790f58eb67ee9eb52c5f Mon Sep 17 00:00:00 2001
From: Eric Mertens <emertens@gmail.com>
Date: Tue, 15 Apr 2008 18:04:30 -0700
Subject: [PATCH 2/2] Add project-euler solution no. 76

---
 extra/project-euler/076/076.factor | 53 ++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 extra/project-euler/076/076.factor

diff --git a/extra/project-euler/076/076.factor b/extra/project-euler/076/076.factor
new file mode 100644
index 0000000000..b09a2742c3
--- /dev/null
+++ b/extra/project-euler/076/076.factor
@@ -0,0 +1,53 @@
+! Copyright (c) 2008 Eric Mertens
+! See http://factorcode.org/license.txt for BSD license.
+USING: arrays assocs combinators kernel math sequences math.ranges locals ;
+IN: project-euler.076
+
+! http://projecteuler.net/index.php?section=problems&id=76
+
+! DESCRIPTION
+! -----------
+
+! How many different ways can one hundred be written as a
+! sum of at least two positive integers?
+
+! SOLUTION
+! --------
+
+! This solution uses dynamic programming and the following
+! recurence relation:
+
+! ways(0,_) = 1
+! ways(_,0) = 0
+! ways(n,i) = ways(n-i,i) + ways(n,i-1)
+
+<PRIVATE
+
+: init ( n -- table )
+    [1,b] [ 0 2array 0 ] H{ } map>assoc
+    1 { 0 0 } pick set-at ;
+
+: use ( n i -- n i )
+    [ - dup ] keep min ; inline
+
+: ways ( n i table -- )
+    over zero? [
+        3drop
+    ] [
+        [ [ 1-  2array ] dip at     ]
+        [ [ use 2array ] dip at +   ]
+        [ [     2array ] dip set-at ] 3tri
+    ] if ;
+
+:: each-subproblem ( n quot -- )
+    n [1,b] [ dup [1,b] quot with each ] each ; inline
+
+PRIVATE>
+
+: (euler076) ( n -- m )
+    dup init
+    [ [ ways ] curry each-subproblem ]
+    [ [ dup 2array ] dip at 1- ] 2bi ;
+
+: euler076 ( -- m )
+    100 (euler076) ;