Integer to Roman - Leetcode 12 - Python

0:00 - Read the problem
1:40 - Drawing Explanation
6:25 - Coding Explanation

leetcode 12

#amazon #interview #python
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[aryanyadav]

Great explanation!
I don't even go through the discuss section if NeetCode's video is available.

[gary-williams]

The division and modulus can be replaced with subtraction:

for sym, val in reversed(symList):
while num >= val:
res += sym
num -= val


This won't perform any different (although there will be 3x as many string concatenations in the worst case (e.g., num=3333) ), but it's conceptually slightly simpler.

[andresbonelli]

Cool explanation!
Another possible solution:

def intToRoman(self, num: int) -> str:
symList = [...] # (Your symbols list)

# Roman zero does not exist
if num <= 0:
return None
result = ""
for symbol, value in reversed(symList):
while value <= num:
result += symbol
num -= value
return result

[mengjiasings]

Thanks for your work! I am trying to develop a habit of watching your video everyday before bed.

[katrinak]

Best explanations out there. Your videos are so succinct and well explained that I can understand any problem in about ten minutes! Got a Youtube account just so I could subscribe and support the channel as a thank you! So thank you!!

[parkboy]

As of Python 3.7 hashmap (dict) preserves insertion order so you don't need to use a list.

[self-learning]

Thanks for the great explaination! Just a quick ques: Why did you use list instead if hashmap? I have an idea still wanted some clarification if what I thinking is right.

[arunks]

Best in youtube. To the point, short but complete 👍

[adventurer]

Your explanations are excellent! After watching many of your videos, one suggestions I would make is better variable naming for clarity. Your variable names tend too be too concise and generic/unclear. In this video for example, "sym, val" would be clearer as "roman, decimal". I see you also use "res" a lot in many of your videos. Sometimes, I have to re-read the code a few times to keep track of what the variables mean. Other than that, awesome, and thank you so much for helping us!

[dhirojkumarsahu]

how to handle 400, the output is "CCCC" but expected is "CD". I think To handle the case of 400, we need to add an additional condition to check if the num is equal to the current val. If that condition is true, we can directly append the symbol and subtract the value from num. This will ensure the code correctly handles cases requiring subtractive notation.

[rpgiri]

Thanks dude. Your simple explanation is superb.

[travelnlearn]

You explained it like a peice of a cake

[jpkeys]

The only thing I can say is: Thank you, thank you, thank you!!!

[nehascorpion]

Woah! That was an outstanding explanation. Extremely clear and concise. Thanks a ton!

[safwan]

Is it not mandatory to give an (!= 0) in the if statement?

[LordKing]

like+subscribed! thx for the help! I m learning a lot with your channel bro!

[athangkulkarni]

Can we use LinkedHashMap and iterate through it? Complexity to retrieve an element would be reduced

[ivanleon]

I have a different solución, but tours is good to me too.

[ISHSACHDEVA-ir]

Stop the iteration if num==0:
if num==0:
return res

[oyeshetty]

What about the number 1000, it shows CDCDXCXCXX instead of M which is already in the array