init

1 files changed, 22 insertions, 0 deletions

diff --git a/6-kyu/valid-braces.hs b/6-kyu/valid-braces.hs
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+-- https://www.codewars.com/kata/5277c8a221e209d3f6000b56
+
+module Codewars.Kata.Braces where
+
+validBraces :: String -> Bool
+validBraces xs = impl 0 0 0 xs where
+  impl cnt1 cnt2 cnt3 str =
+    if str == [] then
+      cnt1 == 0 && cnt2 == 0 && cnt3 == 0
+    else let
+      x = head str
+      xs = tail str
+    in
+      if cnt1 < 0 || cnt2 < 0 || cnt3 < 0 then
+        False
+      else if x == '(' then impl (cnt1 + 1) cnt2 cnt3 xs
+      else if x == ')' then impl (cnt1 - 1) cnt2 cnt3 xs
+      else if x == '[' then impl cnt1 (cnt2 + 1) cnt3 xs
+      else if x == ']' then impl cnt1 (cnt2 - 1) cnt3 xs
+      else if x == '{' then impl cnt1 cnt2 (cnt3 + 1) xs
+      else if x == '}' then impl cnt1 cnt2 (cnt3 - 1) xs
+      else False