LeetCode-12. Integer to Roman

[ninehills]

问题

https://leetcode.com/problems/integer-to-roman/#/description

Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999.

https://en.wikipedia.org/wiki/Roman_numerals

Symbol	I	V	X	L	C	D	M
--	1	5	10	50	100	500	1,000

思路

罗马计数法看起来复杂，其实可以和十进制有个一一对应关系

分位-数字	0	1	2	3	4	5	6	7	8	9
个位	""	I	II	III	IV	V	VI	VII	VIII	IX
十位	""	X	XX	XXX	XL	L	LX	LXX	LXXX	XC	C
百位	""	C	CC	CCC	CD	D	DC	DCC	DCCC	CM	MC
千位	""	M	MM	MMM

解决

package main

import "fmt"

// ----------------------
func intToRoman(num int) string {
    r1 := []string{"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"}
    r2 := []string{"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"}
    r3 := []string{"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"}
    r4 := []string{"", "M", "MM", "MMM"}
    return fmt.Sprintf("%v%v%v%v", r4[num/1000], r3[num%1000/100], r2[num%100/10], r1[num%10])
}

// ----------------------

func main() {
    fmt.Println(intToRoman(90))
    fmt.Println(intToRoman(131))
    fmt.Println(intToRoman(13))
}

[ninehills]

20170721