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 before V (5) and X (10) to make 4 and 9. X can be placed before L (50) and C (100) to make 40 and 90. C can be placed before D (500) and M (1000) to make 400 and 900. Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999.
Example 1:
Input: 3
Output: "III"
Example 2:
Input: 4
Output: "IV"
Example 3:
Input: 9
Output: "IX"
Example 4:
Input: 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.
Example 5:
Input: 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
//32ms
<?php
/**
* Created by PhpStorm.
* User: zhanglingyu
* Date: 2019-04-10
* Time: 12:41
*/
class Solution {
/**
* @param Integer $num
* @return String
*/
function intToRoman($num) {
$value = array('M' => 1000, 'CM' => 900, 'D' => 500, 'CD' => 400, 'C' => 100, 'XC' => 90, 'L' => 50, 'XL' => 40, 'X' => 10, 'IX' => 9, 'V' => 5, 'IV' => 4, 'I' => 1);
$result = '';
foreach ($value as $key => $value) {
if ($num < $value) { continue; }
$times = floor($num / $value);
$num = $num % $value;
$result .= str_repeat($key, $times);
}
return $result;
}
}
class Test extends \PHPUnit\Framework\TestCase
{
/** @test */
public function testSolution()
{
$solution = new Solution();
$int1 = 3;
$this->assertEquals($solution->intToRoman($int1), 'III');
}
}
无
// 24ms
/**********************************************
** @Des: 12 - main
** @Author: zhanglingyu
** @Date: 2019-04-10 12:48
** @Last Modified time: 2019-04-10 12:48
***********************************************/
package main
import (
"fmt"
"math"
"strings"
)
func main() {
i1 := 883
fmt.Println(intToRoman(i1))
}
func intToRoman(num int) string {
var m map[string]int
m = map[string]int{"M":1000, "CM":900, "D":500, "CD":400, "C":100, "XC":90, "L":50, "XL":40, "X":10, "IX":9, "V":5, "IV":4, "I":1 }
c := []string{"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"}
var res string
for _, value := range c {
v := m[value]
if num < v {
continue
}
times := math.Floor(float64(num/v))
num = num%v
res += strings.Repeat(value, int(times))
}
return res
}
/*
golang map没有顺序
*/
// 24ms
func intToRoman(num int) string {
var result []byte
if num>=1000{
xx:=num/1000
for i:=0;i<xx;i++{
result=append(result,'M')
}
}
num=num%1000
if num>=100{
switch num/100{
case 1:
result=append(result,'C')
case 2:
result=append(result,'C','C')
case 3:
result=append(result,'C','C','C')
case 4:
result=append(result,'C','D')
case 5:
result=append(result,'D')
case 6:
result=append(result,'D','C')
case 7:
result=append(result,'D','C','C')
case 8:
result=append(result,'D','C','C','C')
case 9:
result=append(result,'C','M')
}
}
num=num%100
if num>=10{
switch num/10{
case 1:
result=append(result,'X')
case 2:
result=append(result,'X','X')
case 3:
result=append(result,'X','X','X')
case 4:
result=append(result,'X','L')
case 5:
result=append(result,'L')
case 6:
result=append(result,'L','X')
case 7:
result=append(result,'L','X','X')
case 8:
result=append(result,'L','X','X','X')
case 9:
result=append(result,'X','C')
}
}
num=num%10
switch num{
case 1:
result=append(result,'I')
case 2:
result=append(result,'I','I')
case 3:
result=append(result,'I','I','I')
case 4:
result=append(result,'I','V')
case 5:
result=append(result,'V')
case 6:
result=append(result,'V','I')
case 7:
result=append(result,'V','I','I')
case 8:
result=append(result,'V','I','I','I')
case 9:
result=append(result,'I','X')
}
return string(result)
}
方法一一般是自己实现的方法，其他方式是在discuss中查找的更为优秀的方法，用作学习和借鉴。