IP_AMAZON.cpp

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define loop(i, start, end) for (int i = start; i <= end; i++)
#define rloop(i, start, end) for (int i = start; i >= end; i--)
#define vi vector<int>
#define vec(x) vector<x>
#define sz(v) (int)v.size() 
#define UB upper_bound
#define LB lower_bound
#define all(v) (v).begin(),(v).end()
#define arl(v) (v).rbegin(),(v).rend()
#define fsp(a) fixed<<setprecision(a)
#define mem(a,with) memset(a, with, sizeof (a))
#define vmn(a) (*min_element(a.begin(),a.end()))   
#define vmx(a) (*max_element(a.begin(),a.end()))
#define bs(a,key) binary_search(all(a),key)    /// return bool.
#define rotl(a,x) rotate(a.begin(),a.begin()+x,a.end());
#define rotr(a,x) rotl(a,a.size()-x);
#define nl cout<<endl
#define dbg(x) cerr << #x << " :: " << x << endl;
#define dbg2(x, y) cerr << #x << " :: " << x << "\t" << #y << " :: " << y << endl;
#define MOD 1000000007
int add(int x, int y) {int res = x + y; return (res >= MOD ? res - MOD : res);}
int mul(int x, int y) {int res = x * y; return (res >= MOD ? res % MOD : res);}
int power(int x, int y) {int res = 1; x %= MOD; while (y) {if (y & 1)res = mul(res, x); y >>= 1; x = mul(x, x);} return res;}

vector<vi> ans;
vi arr,temp;
int n,k;

void f(int idx,int sum){

    if(sum==k){
        ans.push_back(temp);
        return;
    }

    if(idx>=n or sum>k) return;

    f(idx+1,sum);
    temp.push_back(arr[idx]);
    f(idx+2,sum+arr[idx]);
    temp.pop_back();
}

void solve(){
    //code goes here
    cin>>n>>k;
    arr.resize(n);
    loop(i,0,n-1) cin>>arr[i];

    f(0,0);

    if(ans.size()==0){
        cout<<-1;
        return;
    }

    for(auto it:ans){
        for(auto x:it){
            cout<<x<<" ";
        }
        nl;
    }
}

int32_t main()
{
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
ios_base::sync_with_stdio(false);
cout.tie(NULL);
cin.tie(NULL);
    int t=1;
    // cin>>t;
    while (t--)
    {
        solve();
    }
    return 0;
}