在本例中,为什么会生成正确的结果:
nxt = path + [nums[i]]
但不是:
nxt = path ; nxt += [nums[i]]
nxt = path ; nxt.append(nums[i])
def permute(nums):
def dfs(nums, path):
if not nums: # empty, done with path
all_perms.append(path)
return
for i in range(len(nums)):
nxt = path + [nums[i]]
# nxt = path ; nxt += [nums[i]]
# nxt = path ; nxt.append(nums[i])
print(nxt)
dfs(nums[:i] + nums[i+1:], nxt)
all_perms = []
dfs(nums, [])
return all_perms
