Integer to Roman - Leetcode 12

Integer to Roman - Leetcode 12 - Python

Рет қаралды 77,699

Күн бұрын

Пікірлер: 72

@andresbonelli 6 ай бұрын

Cool explanation! Another possible solution: def intToRoman(self, num: int) -> str: symList = [...] # (Your symbols list) # Roman zero does not exist if num

@balu45653 5 ай бұрын

it works fine bro

@RichardSmith-os2hk 24 күн бұрын

STOP ITTTTTTTTTTTTTTTTTTTTTTTTTT I WANTED TO SOLVE IT NUMBNUTS

@aryanyadav3926 2 жыл бұрын

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

@mengjiasings1278 3 жыл бұрын

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

@priyanshu715 3 жыл бұрын

after bed will give you better result

@bigboyshassen59 6 күн бұрын

Here you go kings and queens, save yourself some time: symList = [["I", 1], ["IV", 4], ["V", 5], ["IX", 9], ["X", 10], ["XL", 40], ["L", 50], ["XC", 90], ["C", 100], ["CD", 400],["D", 500],["CM", 900],["M", 1000]]

@gary-williams 8 ай бұрын

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.

@katrinak3469 2 жыл бұрын

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

@arunks4918 3 жыл бұрын

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

@parkboy 9 ай бұрын

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

@jpkeys6000 Жыл бұрын

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

@adventurer2395 Жыл бұрын

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!

@travelnlearn Жыл бұрын

You explained it like a peice of a cake

@rpgiri2002 2 ай бұрын

Thanks dude. Your simple explanation is superb.

@self-learning1824 2 жыл бұрын

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.

@jpkeys6000 Жыл бұрын

Because you need to iterate in order. A dictionary key-value pair has no order.

@Mis_guidedz 11 ай бұрын

@@jpkeys6000they do in python …

@nehascorpion 2 жыл бұрын

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

@LordKing13 3 жыл бұрын

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

@MideStudio Жыл бұрын

Thank you a lot, from France !

@ayonnnnnnn 3 ай бұрын

u made it so easy man thanks

@maxrivera3275 Жыл бұрын

Hermosa solución. Simple y efectiva.

@imomuganda 2 жыл бұрын

Simple and brilliant.

@arsenearteta 4 ай бұрын

Here's how I did it if anyone wants an alternate solution: class Solution(object): def intToRoman(self, num): integers=[1000,900,500,400,100,90,50,40,10,9,5,4,1] roman=['M','CM','D','CD','C','XC','L','XL','X','IX','V','IV','I'] rom_val=[] while(num!=0): for i in range(len(integers)): while(num>=integers[i]): rom_val.append(roman[i]) num=num-integers[i] return ''.join(rom_val) or alternatively: class Solution(object): def intToRoman(self, num): integers=[1000,900,500,400,100,90,50,40,10,9,5,4,1] roman=['M','CM','D','CD','C','XC','L','XL','X','IX','V','IV','I'] rom_val=[] i=0 while(num!=0): for i in range(len(integers)): count=num//integers[i] rom_val.append(roman[i]*count) num=num%integers[i] return ''.join(rom_val)

@052dhirojkumarsahu9 Жыл бұрын

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.

@animeshsingh4290 Жыл бұрын

It's already in the list of our conditions

@ivanleon6164 Жыл бұрын

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

@aaryandubey6906 Жыл бұрын

Good Explanation

@ISHSACHDEVA-i9r 2 ай бұрын

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

@69savage75 3 жыл бұрын

Good video sir.

@Technical-zero 5 ай бұрын

thank you for your help😀

@DatascienceConcepts 3 жыл бұрын

Such a clear explanation!

@owenwu7995 Жыл бұрын

This is more math than programming

@athangkulkarni8245 Жыл бұрын

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

@parkboy 9 ай бұрын

Yes you can and as of Python 3.7 the hashmap preserves insertion order.

@dannyhd8301 2 жыл бұрын

absolutely amazing

@chenhaibin2010 2 жыл бұрын

such an elegant solution

@safwan1340 9 ай бұрын

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

@dingus2332 5 ай бұрын

You could have avoided the complexity of reversing the list , simply making the list reverse from the start

@data_science_uzbekistan 8 ай бұрын

thanks for your help for beginners like me 😂

@edwardteach2 2 жыл бұрын

U a Roman God

@LevelUpJourney-d2d 2 жыл бұрын

thank you so much

@FaberLSH 4 ай бұрын

Awesome!!

@oyeshetty 2 жыл бұрын

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

@Dhanushh 2 жыл бұрын

1000 / 1000 gives count 1. which then multiplied with M gives you M alone. Then num becomes 0 due to mod operation. loop breaks

@איתיבןחיים-ט6מ 2 жыл бұрын

What about the number 8? In roman numerals its VIII, but if I'm not mistaken according to this code it'd be IVIV

@OGRfilms 2 жыл бұрын

Remember that we iterate through the table in reverse order. 8 would first be divided by 5, which would be divisible once (integer division), so count would be 1 for 5 and we would add 'V' and then mod by 5 to get 3, which would then be divided by 1, producing a count of 3 and adding 'I' 3 times

@איתיבןחיים-ט6מ 2 жыл бұрын

@@OGRfilms oh got it, thank you

@quandingleberry445 Ай бұрын

If num is 8000 wouldn't this give 8 M's?

@uqu200 2 жыл бұрын

for 1994 it's giving wrong answer

@rajanmaheshwari 2 жыл бұрын

No, it gives the right answer i.e "MCMXCIV". However I did in Swift, but the concept is same

@sutriptaroy 2 жыл бұрын

Yes, for 1994, it's not working

@abhineetsingh6720 2 жыл бұрын

it works perfectly , just now submitted it with the same logic

@johnniegilkerson4724 5 ай бұрын

ok how do you run it with no main?

@finwwwfinwww4669 2 жыл бұрын

Am i the only one in 30s and still struggling with such problems :(

@KTBWorld 2 жыл бұрын

I'm pretty sure that line 10 of your code "if num // val:" is unnecessary. In fact, the following few lines don't need to be nested into any conditionals at all; The line is redundant with the following line, since "count" is only going to be altered in cases where "num" is larger than "val" anyway. If you take out the conditional, the code still passes all of LeetCode's tests and accepts the submission as correct. That said, I'm still pretty new to this, so maybe there's another reason here that I'm missing. Would adding that conditional allow the program to run faster, as the processor wouldn't need to run through the following lines for "value" values that aren't going to change the result? LeetCode doesn't give noticeably different CPU usages or speeds for the two different versions of the code, but I can imagine that maybe this is something that would only be an issue in longer and more complex software.