added one/three.scm

1 files changed, 32 insertions, 0 deletions

diff --git a/one/three.scm b/one/three.scm
new file mode 100644
index 0000000..53a8a3c
--- /dev/null
+++ b/one/three.scm
@@ -0,0 +1,32 @@
+(define-module (one three)
+  #:export (square sum-of-squares largest first-arg-2nd-largest-p
+                   sum-of-squares-of-largest-two))
+
+(define (square x) (* x x))
+
+(define (sum-of-squares x y)
+  (+ (square x) (square y)))
+
+(define (largest x y z)
+  (cond ((and (>= x y)
+              (>= x z)) x)
+        ((and (>= y x)
+              (>= y z)) y)
+        ((and (>= z x)
+              (>= z y)) z)))
+
+(define (first-arg-2nd-largest-p x y z)
+  (or (and (>= x y)
+           (<= x z))
+      (and (<= x y)
+           (>= x z))
+      ))
+
+(define (sum-of-squares-of-largest-two x y z)
+  (sum-of-squares (largest x y z)
+                  (cond ((first-arg-2nd-largest-p x y z)
+                         x)
+                        ((first-arg-2nd-largest-p y x z)
+                         y)
+                        ((first-arg-2nd-largest-p z x y)
+                         z))))