Basic Recursion, Check Balanced Parenthesis

Question

I\'ve written software in the past that uses a stack to check for balanced equations, but now I\'m asked to write a similar algorithm recursively to check for properly neste

Answer 1

func evalExpression(inStringArray:[String])-> Bool{
    var status = false
    var inStringArray = inStringArray
    if inStringArray.count == 0 {
        return true
    }

    // determine the complimentary bracket.
    var complimentaryChar = ""
    if (inStringArray.first == "(" || inStringArray.first == "[" || inStringArray.first == "{"){
        switch inStringArray.first! {
        case "(":
            complimentaryChar = ")"
            break
        case "[":
            complimentaryChar = "]"
            break
        case "{":
            complimentaryChar = "}"
            break
        default:
            break
        }
    }else{
        return false
    }

    // find the complimentary character index in the input array.
    var index = 0
    var subArray = [String]()
    for i in 0..