[LeetCode] 77. Combinations (Python)

• Reference

Solution

from typing import List


class Solution:
    # [1, n] -> (1, n + 1) 범위
    def combine(self, n: int, k: int) -> List[List[int]]:
        answer = []

        def dfs(start: int, index: int, elements: List[int]) -> None:
            if len(elements) == k:
                answer.append(elements[:])
                return

            for i in range(start, n + 1):
                elements.append(i)
                dfs(i + 1, index + 1, elements)
                elements.pop()

        dfs(1, k, [])

        return answer

Itertools Solution

import itertools
from typing import List


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