Python describe LeetCode 77. Combine

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subject

Given two integers n and k, Return range [1, n] All the possibilities in k Combination of numbers .

You can press In any order Return to the answer .

Example 1：

 Input ：n = 4, k = 2
Output ：
[
[2,4],
[3,4],
[2,3],
[1,2],
[1,3],
[1,4],
]

Example 2：

 Input ：n = 1, k = 1
Output ：[[1]]

Tips ：

• 1 <= n <= 20
• 1 <= k <= n

Python describe

Explosive search

class Solution:
def combine(self, n: int, k: int) -> List[List[int]]:
res = []
tmp = []
def dfs(num,idx):
nonlocal n,k
if idx == k:
res.append(copy.deepcopy(tmp))
return
if idx <= k-1 and num <= n:
for i in range(num,n+1):
tmp.append(i)
dfs(i+1,idx+1)
tmp.pop()
dfs(1,0)
return res