12. Integer to Roman

最新推荐文章于 2024-01-03 14:56:38 发布

原创最新推荐文章于 2024-01-03 14:56:38 发布 · 91 阅读

0 ·

CC 4.0 BY-SA版权

leetcode 专栏收录该内容

88 篇文章

订阅专栏

本文详细介绍罗马数字的基本符号及其表示的数值，解释了特殊组合规则，如IV表示4，IX表示9，并提供了将阿拉伯数字转换为罗马数字的方法。通过实例演示，如数字3转换为III，4转换为IV，1994转换为MCMXCIV。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

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.

class Solution(object):
    def intToRoman(self, num):
        """
        :type num: int
        :rtype: str
        """
        M = ["", "M", "MM", "MMM"]
        C = ["", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"]
        X = ["", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"]
        I = ["", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"]
        return M[num/1000] + C[(num%1000)/100] + X[(num%100)/10] + I[num%10]

class Solution(object):
    def intToRoman(self, num):
        """
        :type num: int
        :rtype: str
        """
        values = [ 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 ]
        numerals = [ "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" ]
        list = ''
        for i in range(0, len(values)):
            while num >= values[i]:
                num -= values[i]
                list += numerals[i]
        return list