finish vol 10

1 files changed, 34 insertions, 0 deletions

diff --git a/90-94/93.hs b/90-94/93.hs
new file mode 100644
index 0000000..c031e7b
--- /dev/null
+++ b/90-94/93.hs
@@ -0,0 +1,34 @@
+puzzle :: [Integer] -> [String]
+
+puzzle l = do i <- [1..length l-1]
+              let (subl, subr) = splitAt i l
+              (sl, vl, _) <- gen subl
+              (sr, vr, _) <- gen subr
+              if vl == vr then
+                  return (sl ++ " = " ++ sr)
+              else []
+
+gen :: [Integer] -> [(String, Rational, String)]
+gen (x:[]) = return (show x, fromInteger x, "_")
+
+gen l = do i <- [1..length l-1]
+           let (subl, subr) = splitAt i l
+           (sl, vl, opsl) <- gen subl
+           (sr, vr, opsr) <- gen subr
+           (ops, op) <- [("+", (+)), ("-", (-)), ("*", (*)), ("/", (/))]
+           if (ops == "/" && vr == 0) ||
+               (ops == "+" && (opsr == "+" || opsr == "-")) ||
+               (ops == "*" && (opsr == "*" || opsr == "/")) then []
+           else
+              return ((if opsl /= "_" &&
+                          (ops == "*" || ops == "/") &&
+                          (opsl == "+" || opsl == "-") then
+                           "(" ++ sl ++ ")"
+                      else sl)
+                      ++ " " ++ ops ++ " " ++
+                      (if opsr /= "_" &&
+                           ((ops == "-" && opsr /= "*" && opsr /= "/") ||
+                           (ops == "*" && (opsr == "+" || opsr == "-")) ||
+                           ops == "/") then
+                           "(" ++ sr ++ ")"
+                      else sr), op vl vr, ops)