class Solution {
public:
    vector<vector<int>> ans;
    vector<int> path;
    vector<vector<int>> combinationSum2(vector<int>& c, int target) {
        sort(c.begin(), c.end());
        dfs(c, 0, target);
        return ans;
    }

    void dfs(vector<int>& c, int u, int target) {
        if (target == 0) {
            ans.push_back(path);
            return ;
        }
        if (u == c.size()) return ;

        int k = u + 1;
        while (k < c.size() && c[k] == c[u]) k ++;
        int cnt = k - u;

        for (int i = 0; i * c[u] <= target && i <= cnt; i ++) {
            dfs(c, k, target - i * c[u]);
            path.push_back(c[u]);
        }

        for (int i = 0; i * c[u] <= target && i <= cnt; i ++) 
            path.pop_back();
    }
};