#include <bits/stdc++.h>
using namespace std;
 
void f(vector<int>&v,vector<vector<int>>ans,vector<int>temp,int idx, int& sum, int k){
	if(idx>=(int)v.size() || sum==k){
		if(sum==k) ans.push_back(temp);
		return;
	}
	sum=sum+v[idx];temp.push_back(v[idx]);
	f(v,ans,temp,idx+1,sum,k);
	sum=sum-v[idx];
	temp.pop_back();
	f(v,ans,temp,idx+1,sum,k);
}
 
int main() {
	vector<int> v = {3, 1, 2};
    vector<int> temp;
    vector<vector<int>> ans;
	int sum=0;
    f(v,ans,temp,0,sum,3);
 
    for (const auto& seq : ans) {
        for (int num : seq)
            cout << num << " ";
        cout << endl;
    }
}

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