# Question

Formatted question description: https://leetcode.ca/all/254.html

 254	Factor Combinations

Numbers can be regarded as product of its factors. For example,

8 = 2 x 2 x 2;
= 2 x 4.
Write a function that takes an integer n and return all possible combinations of its factors.

Note:
Each combination's factors must be sorted ascending, for example: The factors of 2 and 6 is [2, 6], not [6, 2].
You may assume that n is always positive.
Factors should be greater than 1 and less than n.

Examples:

input: 1
output:
[]

input: 37
output:
[]

input: 12
output:
[
[2, 6],
[2, 2, 3],
[3, 4]
]

input: 32
output:
[
[2, 16],
[2, 2, 8],
[2, 2, 2, 4],
[2, 2, 2, 2, 2],
[2, 4, 4],
[4, 8]
]



# Algorithm

Iterate from 2 to n. If the current number i is divisible by n, it means that i is a factor of n. Store it in a onePath list, and then recursively call n/i. At this time, do not traverse from 2. It traverses from i to n/i, and the condition for stopping is when n is equal to 1, if there is a factor in onePath at this time, store this combination in the result.

### Pitfall

Need to avoid case: n=32, and only 32 in this list, add check if (onePath.size() > 1)

Java