Subsets

Given a set of distinct integers, S, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. For example, if S = [1,2,3], a solution is: [ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ].

回溯法，代码如下：

void subset(vector<int> vecInt)
{
    sort(vecInt.begin(), vecInt.end());
    vector<int> vecWorker;
    subsetsHelper(vecWorker, vecInt, 0);
}

void subsetHelper(vector<int>& vecWorker, const vector<int>& vecInt, int pos)
{
    outputToResult(vecWorker);

    for (int i = pos; i < vecInt.length(); i++)
    {
        vecWorker.push_back(vecInt[i]);
        subsetHelper(vecWorker, vecInt, i+1);
        vecWorker.pop_back();
    }
}