标签：span clu integer elf exclude col size ons solution
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:
Example 1:
Input: 1
Output: []
Example 2:
Input: 37
Output:[]
Example 3:
Input: 12
Output:
[
[2, 6],
[2, 2, 3],
[3, 4]
]
Example 4:
Input:32Output: [ [2, 16], [2, 2, 8], [2, 2, 2, 4], [2, 2, 2, 2, 2], [2, 4, 4], [4, 8] ]
class Solution { public List<List<Integer>> getFactors(int n) { List<List<Integer>> res = new ArrayList<>(); helper(res, new ArrayList<>(), n, 2); return res; } private void helper(List<List<Integer>> res, List<Integer> list, int n, int start) { if (n == 1) { // exclude the self case if (list.size() > 1) { res.add(new ArrayList<>(list)); return; } } for (int i = start; i <= n; i++) { if (n % i == 0) { list.add(i); helper(res, list, n / i, i); list.remove(list.size() - 1); } } } }
标签：span clu integer elf exclude col size ons solution
原文地址：https://www.cnblogs.com/xuanlu/p/12508886.html
