class Solution {
public:
    vector<vector<int>> ans;
    vector<int> path;
    vector<vector<int>> combinationSum(vector<int>& c, int target) {
        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;
        for(int i=0;c[u]*i<=target;i++)
        {
            dfs(c, u+1, target-c[u]*i);
            path.push_back(c[u]);
        }
        for(int i=0;c[u]*i<=target;i++)
        {   
            path.pop_back();
        }
    }
};