[LeetCode][python3]0012. Integer to Roman

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N2I -2020.03.17

1. A clean solution

class Solution:
    def intToRoman(self, num: int) -> str:
        rom = ["M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"]
        digit = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
        result = ""
        
        for d, r in zip(digit, rom):
            result += r * (num // d)
            num %= d 
        return result
 

Note:

• zip(a,b) The function zip will zip two array items into a two tuple array. the zip array will stop when it reaches min(len(a),len(b))

print("example of zip(a,b)")
a=[1,2,3,4,5]
b='abcdef'
for n in zip(a,b):
    print(n)
>>>(1, 'a')
>>>(2, 'b')
>>>(3, 'c')
>>>(4, 'd')
>>>(5, 'e')

2. My first try

class Solution:
    def intToRoman(self, num: int) -> str:
        M=num//1000
        num=num%1000
        D=num//500
        num=num%500
        C=num//100
        num=num%100
        L=num//50
        num=num%50
        X=num//10
        num=num%10
        V=num//5
        I=num%5
        s=""
        if I==4:
            if V==0:
                s="IV"
            else:
                s="IX"
                V-=1
        else:
            s="I"*I
        s="V"*V+s
        if X==4:
            if L==0:
                s="XL"+s
            else:
                s="XC"+s
                L-=1
        else:
            s="X"*X+s
        s="L"*L+s
        if C==4:
            if D==0:
                s="CD"+s
            else:
                s="CM"+s
                D-=1
        else:
            s="C"*C+s
        s="D"*D+s
        s="M"*M+s
        return s
 

Explanation:

A normal way to solve this problem. It is a bit faster but a longer code. I check out the special cases only when I=4,X=4,C=4.