菜菜的刷题日记 | 12.整数转罗马数字

系列索引：菜菜的刷题日记 | 被LeetCode用Python狂虐的那段日子

菜鸡的刷题之路——2022/1/24，这几天忙着肝并发编程，题在做但是没空写题解，今晚补一篇。

【题目】

题目链接：https://leetcode-cn.com/problems/integer-to-roman/

【官方思路】

方法一：模拟

class Solution:

    VALUE_SYMBOLS = [
        (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"),
    ]

    def intToRoman(self, num: int) -> str:
        roman = list()
        for value, symbol in Solution.VALUE_SYMBOLS:
            while num >= value:
                num -= value
                roman.append(symbol)
            if num == 0:
                break
        return "".join(roman)
        

方法二：硬编码数字

class Solution:

    THOUSANDS = ["", "M", "MM", "MMM"]
    HUNDREDS = ["", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"]
    TENS = ["", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"]
    ONES = ["", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"]

    def intToRoman(self, num: int) -> str:
        return Solution.THOUSANDS[num // 1000] + \
            Solution.HUNDREDS[num % 1000 // 100] + \
            Solution.TENS[num % 100 // 10] + \
            Solution.ONES[num % 10]

【我的代码】

主要使用了字典的遍历，代码比较简洁易懂，但是效率不高，仅供参考~

class Solution:
    def intToRoman(self, num: int) -> str:
        value = {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'}
        strs = ""
        for key, val in value.items():
            while num >= key:
                num -= key
                strs += val
        return strs

【思考】

早睡早起是我遥不可及的梦

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