39. Combination Sum
Given a set of candidate numbers (C) (without duplicates) 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.
- 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]
]
Solution: DFS
class Solution(object):
def combinationSum2(self, candidates, target):
"""
:type candidates: List[int]
:type target: int
:rtype: List[List[int]]
"""
candidates.sort()
combinations = []
combination = []
def dfs(start, remain):
if remain < 0:
return
if remain == 0:
combinations.append(list(combination))
return
for idx in xrange(start, len(candidates)):
num = candidates[idx]
if idx > start and num == candidates[idx - 1]:
continue
combination.append(num)
dfs(idx + 1, remain - num)
combination.pop()
dfs(0, target)
return combinations