【Leetcode】13. Roman numeral to integer

Bowen author wangzirui32
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1. Title Description

source ： Power button （LeetCode）
link ：https://leetcode.cn/problems/roman-to-integer
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2. Their thinking

We can create a dictionary , Take each Roman numeral and Arabic numeral as key value pairs , Form Roman numeral table , And then use for Circular key value pair （k and v）, Detect string s There are several k, There is one k There is one v, You can use multiplication , Then remove all k, then , Enter next cycle , Last result returned .

3. Code implementation

Code：

class Solution:
    def romanToInt(self, s: str) -> int:
    	""" Roman numeral to integer """
    	""" Be careful ： here IV,IX Wait for special Roman numerals in front of the dictionary , This is to avoid conversion errors ."""
        roman_table = {
    
            "IV": 4,
            "IX": 9,
            "XL": 40,
            "XC": 90,
            "CD": 400,
            "CM": 900,
            "I": 1,
            "V": 5,
            "X": 10,
            "L": 50,
            "C": 100,
            "D": 500,
            "M": 1000,
        }
        result = 0  #  result 
        for k, v in roman_table.items():  #  Ergodic dictionary 
            result += s.count(k) * v  #  Inquire about k The number of  * k The value represented (v)
            s = s.replace(k, "")    #  Replace k  Avoid double counting 

        return result

4. final result

Okay , That's all for today's lesson , I am a wangzirui32, You can collect and pay attention to what you like , See you next time ！