Roman numerals are represented by seven different symbols: I
, V
, X
, L
, C
, D
and M
.
Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000
For example, two is written as II
in Roman numeral, just two one's added together. Twelve is written as, XII
, which is simply X
+ II
. The number twenty seven is written as XXVII
, which is XX
+ V
+ II
.
Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII
. Instead, the number four is written as IV
. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX
. There are six instances where subtraction is used:
I
can be placed beforeV
(5) andX
(10) to make 4 and 9.X
can be placed beforeL
(50) andC
(100) to make 40 and 90.C
can be placed beforeD
(500) andM
(1000) to make 400 and 900.
Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999.
Example 1:
Input: "III" Output: 3
Example 2:
Input: "IV" Output: 4
Example 3:
Input: "IX" Output: 9
Example 4:
Input: "LVIII" Output: 58 Explanation: L = 50, V= 5, III = 3.
Example 5:
Input: "MCMXCIV" Output: 1994 Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
package main
import(
"fmt"
"strings"
)
type Dict struct{
key string
value int
}
func romanToInt(s string) int {
var result int
dict := []Dict{{"CM",900},{"M",1000},{"CD",400},{"D",500},{"XC",90},{"C",100},{"XL",40},{"L",50},{"IX",9},{"X",10},{"IV",4},{"V",5},{"I",1}}
for _, v := range dict{
for strings.Index(s, v.key)!=-1{
result = result + v.value
s = strings.Replace(s, v.key, "", 1)
}
if s == ""{
break
}
}
return result
}
func main(){
fmt.Println(romanToInt("MCMXCIV"))
}
中间有一段可以使用下面代码代替,自己编译器上运行时没有问题的,但是使用leetcode的编译器不能识别strings,所以用index代替了
for _, v := range dict{
for i:=strings.Count(s, v.key);i>0;i--{
result = result + v.value
}
s = strings.ReplaceAll(s, v.key, "")
if s == ""{
break
}
}