题目:
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]
解题:
暴力dfs就可以
代码:
class Solution { public: vector<vetor<int> > combinationSum(vector<int> &candidates, int target) { ans.clear(); single.clear(); sort(candidates.begin(), candidates.end()); in = candidates; dfs(0, target); return ans; } private: vector<vector<int> > ans; vector<int> single, in; void dfs(int pos, int target) { if(target == 0) { ans.push_back(single); return ; } for(int i = pos; i < in.size(); i ++) { if(in[i] > target) break; single.push_back(in[i]); dfs(i, target - in[i]); single.pop_back(); } return; } };