HackerEarth Alice and Bob buy crackers problem solution

In this HackerEarth, Alice and Bob buy crackers problem solution Alice and Bob want to buy firecrackers. There are N types of firecrackers available in the market with an ID I ranging from 1 to N. The cost of each firecracker is Ci. Each firecracker can be bought at most once. Bob’s father allows him to spend all the money in any way but his only condition is that Alice and Bob receive equal amounts of money.

Your task is to determine the number of different amounts of money both can receive from Bob’s father. You are given the cost of all crackers and the money according to the condition provided. 

In other words, let S be a set. For each subset of firecrackers, if the sum of the costs of these firecrackers is even, then add their sum to S and print the size of S. Note that the set does not contain equal elements.

#include<bits/stdc++.h>

#define hell                         1000000007
#define lcm(a,b)                     ((a*b)/__gcd(a,b))
#define ll                           long long
#define vll                          vector<ll>
#define vi                           vector<int>
#define pll                          vector< pair<ll,ll> >
#define pb                           push_back
#define mp                           make_pair
#define all(v)                       v.begin(),v.end()
#define lbnd                         lower_bound
#define ubnd                         upper_bound
#define bs                           binary_search
#define F                            first
#define S                            second
#define rep(i,a,b)                   for(i=a;i<b;i++)
#define parr(a,n)                    for(ll it=0;it<n;it++) cout<<a[it]<<" ";cout<<endl;
#define pcont(a)                     for(auto it:a) cout<<it<<" ";cout<<endl;
#define ret(x)                       return cout<<x,0;
#define endl                           'n'

/*constants*/
#define MAXN                         100005
#define PI                           3.14159265358979323846

/*debug*/
#define TRACE
#ifdef TRACE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
    template <typename Arg1>void __f(const char* name, Arg1&& arg1){ std::cout << name << " : " << arg1 << 'n';}
    template <typename Arg1, typename... Args>void __f(const char* names, Arg1&& arg1, Args&&... args){const char* comma = strchr(names + 1, ','); std::cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);}
#else
#define trace(...)
#endif

using namespace std;


int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    
    ll i,j,n,m,k,cnt=0,t=1;
    cin>>n;
        int c[n];
        for(int i=0;i<n;i++){
                cin>>c[i];
        }
        set<int> ans;
        for(int i=1;i<(1<<n);i++){
                int val=0;
                for(int j=0;j<n;j++){
                        if(i&(1<<j)) val+=c[j];
                }
                if(val%2==0) ans.insert(val);
        }
        cout<<ans.size();   
    
    return 0;
}