Solution.py

class Solution:
    def combine(self, n: int, k: int) -> List[List[int]]:
        res = []

        def dfs(i, n, k, t):
            if len(t) == k:
                res.append(t.copy())
                return
            for j in range(i, n + 1):
                t.append(j)
                dfs(j + 1, n, k, t)
                t.pop()

        dfs(1, n, k, [])
        return res