1. 问题描述

给定一个整数，将其转换为罗马数字，要求返回结果的取值范围为1~3999。

2. 问题示例

4→Ⅳ，12→Ⅻ，21→XⅪ，99→XCIX。

3. 代码实现

def int_to_roman(num):val = [1000, 900, 500, 400,100, 90, 50, 40,10, 9, 5, 4,1]syb = ["M", "CM", "D", "CD","C", "XC", "L", "XL","X", "IX", "V", "IV","I"]roman_num = ''i = 0while  num > 0:for _ in range(num // val[i]):roman_num += syb[i]num -= val[i]i += 1return roman_num
print(int_to_roman(4))  # 输出 IV
print(int_to_roman(12))  # 输出 XII
print(int_to_roman(21))  # 输出 XXI
print(int_to_roman(99))  # 输出 XCIX

def int_to_roman(num):roman_dict = {1000: 'M',900: 'CM',500: 'D',400: 'CD',100: 'C',90: 'XC',50: 'L',40: 'XL',10: 'X',9: 'IX',5: 'V',4: 'IV',1: 'I'}roman_num = ''for value, symbol in roman_dict.items():while num >= value:roman_num += symbolnum -= valuereturn roman_num
print(int_to_roman(4))  # 输出 IV
print(int_to_roman(12))  # 输出 XII
print(int_to_roman(21))  # 输出 XXI
print(int_to_roman(99))  # 输出 XCIX