package romantointeger

// 13. 罗马数字转整数
// https://leetcode-cn.com/problems/roman-to-integer/

// IV = 4  IX = 9  XL = 40  XC = 90  CD = 400  CM = 900
// 字符          数值
// I             1
// V             5
// X             10
// L             50
// C             100
// D             500
// M             1000

func romanToInt(s string) int {
	mm := map[string]int{
		"IV": 4,
		"IX": 9,
		"XL": 40,
		"XC": 90,
		"CD": 400,
		"CM": 900,
	}

	m := map[string]int{
		"I": 1,
		"V": 5,
		"X": 10,
		"L": 50,
		"C": 100,
		"D": 500,
		"M": 1000,
	}
	bs := []byte(s)

	var sum int
	l := len(bs)
	for i := 0; i < len(bs); i++ {
		b := string(bs[i])
		if (b == "I" || b == "X" || b == "C") && i+1 != l {
			bn := string(bs[i+1])
			if v, ok := mm[b+bn]; ok {
				sum += v
				i++
			} else {
				sum += m[b]
			}
		} else {
			sum += m[b]
		}
	}

	return sum
}