XRLX.swift

func countSteps(from value: String, _ target: String) -> Int? {
    guard
        value.count == target.count
    else { return nil }
    
    var count = 0
    var newValue = value
    var index = 0
    var found = false
    
    while found == false {
        var found2 = false
        for n in Transformation.allCases {
            let range = newValue.range(of: n.rawValue)
            
            if range != nil {
                newValue.replaceSubrange(range!, with: n.newValue)
                count += 1
                print(newValue, target, range!.lowerBound.hashValue, range!.upperBound.hashValue, count)
                if newValue == target {
                    return count
                }
                found2 = true
            }
        }
        
        if found2 == false {
            found = true
        }
       
    }
    
    
    
    
    return  count
}

enum Transformation: String, CaseIterable {
    case RX
    case XL
    
    var newValue: String {
        switch self {
        case .RX:
            return "RX"
        case .XL:
            return "LX"
        }
    }
}

countSteps(from: "XRX", "XXR")
countSteps(from: "XLXXXRXX", "XXXRLXXX")
countSteps(from: "RXXL", "XRLX")