Help me in solving ANUMLA problem

help
,
1

My issue

I created a subset multiset which stores the subset sums that can be formed till i-1 position using valueSet[1…i-1]. Now if subsetSum[i] is present in subset multiset then I erase it from subset and go to i+1 and if it isn’t present, then I insert subsetSum[i] in my valueSet and insert all new sums that can be formed using this element by looping over subset but it gives tle. how to optimise?

My code

#include <iostream>
#include<bits/stdc++.h>
using namespace std;

using ll = long long;

void solve(){
    int n; cin>>n;
    ll a[1<<n];
    ll c[1<<n]; // subset sums till now
    vector<int> ans;
    for(int i=0; i<(1<<n); i++){
        cin>>a[i];
    }
    sort(a,a+n);
    multiset<int> subsets;
    for(int i=1; i<(1<<n); i++){
        if(subsets.find(a[i])==subsets.end()){
            ans.push_back(a[i]);
            for(int j=1; j<=i-1; j++){
                subsets.insert(a[i]+a[j]);
            }
        }
        else{
            auto it = subsets.find(a[i]);
            subsets.erase(it);
        }
    }
    for(auto x:ans) cout << x << " ";
    cout << "\n";
}

int main() {
	// your code goes here
	int t; cin>>t;
	while(t--){
	    solve();
	}
	return 0;
}

Problem Link: ANUMLA Problem - CodeChef