discard """ action: "run" """ import tables, deques, sequtils const lookupTable = {'(': ')', '{': '}', '[': ']'}.toTable proc isPaired*(value: string): bool = var stack = initDeque[char]() for item in value: # echo "Looking at " & item if item in lookupTable: stack.addLast(item) if item in toSeq(lookupTable.values): if stack.len == 0: return false if lookupTable[stack.popLast()] != item: return false return stack.len == 0 doAssert isPaired("{[()]}") == true doAssert isPaired("a)b(c") == false