Combination SumMar 7 '125736 / 16047
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]
class Solution {
public:
vector<vector<int> > res;
int n;
vector<vector<int> > combinationSum(vector<int> &candidates, int target) {
vector<int> r;
res.clear();
n = candidates.size();
sort(candidates.begin(), candidates.end());
gen(r,0,0, candidates, target);
return res;
}
void gen(vector<int> &r,int sum,int l, const vector<int>& can, int tar) {
if (sum == tar) {
res.push_back(r);
return;
}
if (sum > tar) return ;
for (int i = l; i < n; i++) {
r.push_back(can[i]);
sum += can[i];
gen(r, sum,i, can, tar);
sum -= can[i];
r.pop_back();
}
}
};