77. Combinations

Description:

Given two integers n and k, return all possible combinations of k numbers out of the range [1, n].

You may return the answer in any order.

 

'''
[1] naive solution)

def recur(ans,list,low,k,n):
    if len(list)==k:
        ans.append(list.copy())
        return
    for i in range(low,n+1):
        list.append(i)
        recur(ans,list,i+1,k,n)
        list.pop()

ans=[]
recur(ans,[],1,k,n)
return ans

[2] using python library)

from itetools import combinations

return combinations(range(1,n+1),k)

'''

class Solution:
    def combine(self, n: int, k: int) -> List[List[int]]:
        return combinations(range(1,n+1),k)