Combinations - Leetcode 77 - Recursive Backtracking (Python)

[@GregHogg]

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

[@ARkhan-xw8ud]

I did not get it

[@rhen4610]

my school told me it was gon be just some basic/fundamental coding problem, but then they threw this out there on the medium category of the challenge. Thanks tho!

[@GregHogg]

Haha I see! You're very welcome :P

[@stanleyching123]

Hey Greg, really cool solutions.. but I’m struggling with visualising the recursive backtrack algorithm and the tree. I think it will be helpful if you could run the code line by line in respect with the visual diagram and shows how it work

[@ThoXuanLe]

I think you also need to write on paper to understand deeper, that how I learn recursive.

[@gamasterprochannel856]

couldn't we start with 1 not 4 ?

[@user-jm6gp2qc8x]

Hey Gregg, I am following your vids a lot. I feel that this solution can be modified to be a bit more intuitive for audience

[@nikunjdeeep]

hey greg i enojoy learning from your videos but you could have solved this (1 to n) and not (n to 1) because visulizing first one for a new coder is easier i guess(atleast for me)

[@bilalalfakih1017]

class Solution: def combine(self, n: int, k: int) -> List[List[int]]: result, sol = [], [] def backtrack(i): if len(sol) == k: result.append(sol[:]) return for num in range(i, n + 1): sol.append(num) backtrack(num+1) sol.pop() backtrack(1) return result