LintCode: Combination Sum II

C++

DFS

 class Solution {
 public:
     void help(vector<int> &a, int now, int sum, int target, vector<int> &path, vector<vector<int> > &ans, bool last) {
         if (sum > target) {
             return ;
         }
         if (now >= a.size()) {
             if (sum == target) {
                 ans.push_back(path);
             }
             return ;
         }
         if ((now == ) || (a[now - ] != a[now]) || last) {
             path.push_back(a[now]);
             help(a, now + , sum + a[now], target, path, ans, true);
             path.pop_back();
         }
         help(a, now + , sum, target, path, ans, false);
     }
     /**
      * @param num: Given the candidate numbers
      * @param target: Given the target number
      * @return: All the combinations that sum to target
      */
     vector<vector<int> > combinationSum2(vector<int> &num, int target) {
         // write your code here
         sort(num.begin(), num.end());
         vector<int> path;
         vector<vector<int> > ans;
         help(num, , , target, path, ans, true);
         return ans;
     }
 };