Title: Combination Sum Source: leetcode.com
Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.
The same repeated number may be chosen from C unlimited number of times.
Note:
- All numbers (including target) will be positive integers.
- Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
- The solution set must not contain duplicate combinations.
For example, given candidate set 2,3,6,7 and target 7,
A solution set is:
[7]
[2, 2, 3]
Python solution
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 |
''' https://leetcode.com/problems/combination-sum/ ''' class Solution(object): def __init__(self): self.res = [] self.target = 0 def helper(self, cur, rem, sm): if not rem: return if sm == self.target: self.res.append(sorted(cur)) elif sm < self.target: self.helper(cur + [rem[0]], rem, sm + rem[0]) self.helper(cur, rem[1:], sm) def combinationSum(self, candidates, target): """ :type candidates: List[int] :type target: int :rtype: List[List[int]] """ self.target = target if not candidates: return self.res self.helper([], candidates, 0) return self.res |