Question

How to convert a Roman number to an integer in Scala

Answer 1

object RomanToInteger {

  private val romanMap: Map[Char, Int] = Map(
    'I' -> 1,
    'V' -> 5,
    'X' -> 10,
    'L' -> 50,
    'C' -> 100,
    'D' -> 500,
    'M' -> 1000
  )

  def romanToInt(s: String): Int = {
    var total = 0
    var prevValue = 0

    for (ch <- s.reverse) {
      val currentValue = romanMap(ch)
      if (currentValue < prevValue) {
        total -= currentValue
      } else {
        total += currentValue
      }
      prevValue = currentValue
    }

    total
  }

  def main(args: Array[String]): Unit = {
    val roman = "XCVII"
    val result = romanToInt(roman)

    println(s"The integer value of $roman is $result")
  }
}


/*
XCVII =
XC+V+I+I =
90+5+1+1 =
97
*/



/*
run:

The integer value of XCVII is 97

*/

 

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