[Algorithm] 로마자 숫자로 변환

문제

해결

const roman = {
  'I' : 1,
  'V' : 5,
  'X' : 10,
  'L' : 50,
  'C' : 100,
  'D' : 500,
  'M' : 1000,
}

const romanToNum = s => {
  let arr = s.split("");
  
  let result = arr.reduce((acc, val, idx) => {
    let curVal = roman[val];
    let nextVal = roman[arr[idx + 1]];
  
    if (curVal < nextVal) {
     acc -= curVal
    } else {
      acc += curVal
    }
    return acc;
  }, 0)

  return result;
}