題目描述：
Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.
Each number in candidates may only be used once in the combination.
Note:
- All numbers (including
target) will be positive integers. - The solution set must not contain duplicate combinations.
Example 1:
Input: candidates = [10,1,2,7,6,1,5], target = 8,
A solution set is:
[
[1, 7],
[1, 2, 5],
[2, 6],
[1, 1, 6]
]
Example 2:
Input: candidates = [2,5,2,1,2], target = 5,
A solution set is:
[
[1,2,2],
[5]
]
程序：
class Solution {
public:
vector<vector<int>> combinationSum2(vector<int>& candidates, int target) {
sort(candidates.begin(), candidates.end());
dfs(candidates, target, -1);
for(auto it = st.begin(); it != st.end(); it++) {
res.push_back(*it);
}
return res;
}
private:
vector<int> v;
vector<vector<int>> res;
set<vector<int>> st;
int sum = 0;
void dfs(vector<int>& vec, int target, int index) {
if(sum == target) {
st.insert(v);
return;
}
else if(target < sum) return;
for(int i = index + 1; i < vec.size(); i++) {
v.push_back(vec[i]);
sum += vec[i];
dfs(vec, target, i);
sum -= vec[i];
v.pop_back();
}
}
};
