Daily Temperatures - Leetcode 739 - Stacks (Python)

[@GregHogg]

Master Data Structures & Algorithms For FREE at AlgoMap.io!

[@moonlight-td8ed]

coming to dsa in python, you and neetcode are the BEST

[@alexandermillar3763]

Clear and easily followed visual explination. Thank you!

[@GregHogg]

Thank you and you're very welcome!

[@javeedmahammad2129]

Hey Greg, I think we can modify the code and reduce the complexity of the code. By storing just the indices in the stack, we can directly access the temperature values using these indices, which simplifies the code. This approach makes it more efficient in terms of memory usage, as we're only storing indices rather than tuples containing both temperatures and indices. Here is the code: class Solution: def dailyTemperatures(self, temperatures: List[int]) -> List[int]: n = len(temperatures) stack = [] res = [0] * n for i in range(n): while stack and temperatures[i] > temperatures[stack[-1]]: index = stack.pop() res[index] = i - index stack.append(i) return res

[@sohamarora1837]

This was easier to understand than Neetcode's explanation. Thanks!

[@reginatoronto]

u explain more easily than other channels, although the theory is same, but your explanation was great

[@akashgeorge5433]

you are an MVP wonderfully explained

[@JoeTan-nq4fq]

Traversing backwards and define stack to store indices for i in range(n-1, -1, -1): while stack and temperatures[i] >= temperatures[stack[-1]]: stack.pop() if stack: answer[i] = stack[-1] - i # Store the index offset from ith element stack.append(i)

[@nithin2782]

Excellent explanation. Thanks!! Very helpful

[@mattphillips6623]

I tried to solve this before watching the video and am as embarassed as i am impressed with myself haha. I did end up with a solution for all cases but do i ever have a lot to learn. Great content!

[@GregHogg]

Haha you're doing great! Thanks so much :)

[@chambora1312]

Did I hear a "duck and the lemonade stand" reference at 1:03 😂

[@GregHogg]

You most definitely did haha

[@TTTT-sj3vz]

I did it like this :def dailyTemperatures(self, temperatures: List[int]) -> List[int]: res = [0] * len(temperatures) for i in range(len(temperatures)): for j in range(i+1,len(temperatures)): if temperatures[j] > temperatures[i]: res[i] = j-i break return res but the problem was the time limit, couldn't have thought about the monotonic stack edit why you appended t,i instead i,t ?

[@tejasjoshi9140]

this problem is exact replica of next greater element, its just recognizing patterns, and about the "why t,i and not i,t" you can do it either way

[@pradeepbhat1363]

Is there any way to identify it as a stack pattern ?

[@GregHogg]

This one is monotonic stack where increasing elements kinda start to line up, you might get used to that pattern

[@SemesterAtSeaHopeful]

How do you know its not a two pointer problem?

[@KarthikKumaresan-k1o]

Phenomenal! Thanks

[@GregHogg]

Glad you found it helpful, thanks so much!

[@kickbuttowsk2i]

greg > neetcode, fight me

[@Tigerwolf70]

I don’t like the way you code, bro setting variables to parameters, why not just use the parameter. For example, temps = temperatures. Like bro just use temperatures. Your style of programming is annoying