Magic xor basis code

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

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define subnb true
#define Lnb true
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

const int N = (int)1e5 + 50, B = 60;

struct Ele {
    ll x;
    int tim;
};

int n;
vector<Ele> upd[N];
ll a[N];
map<ll, int> las;
ll bas[B], sz = 0;
int pos[B];
int res[N];
ll pw[B + 1];

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    pw[0] = 1;
    rep(i, 1, B + 1) pw[i] = pw[i - 1] * 2;
    cin >> n;
    rep(i, 0, n) {
        cin >> a[i];
        if(!las.count(a[i]) || las[a[i]] == -1) {
            las[a[i]] = i;
        } else {
            upd[las[a[i]]].push_back({a[i], i - 1});
            las[a[i]] = -1;
        }
    }
    for (auto &p : las) {
        if(p.second != -1) upd[p.second].push_back({p.first, n - 1});
    }
    for(int i = 0; i < n; i++) {
        for (auto [x, nowpos] : upd[i]) {
//            cout << i << " " << nowpos << ": " << x << endl;
            for(int j = B - 1; j >= 0; j--) {
                if(x & (1LL << j)) {
                    if(!bas[j]) {
                        bas[j] = x; pos[j] = nowpos;
                        break;
                    }
                    if(pos[j] < nowpos) {
                        swap(x, bas[j]);
                        swap(nowpos, pos[j]);
                    }
                    x ^= bas[j];
                }
            }
        }
        rep(j, 0, B) {
            res[i] += bas[j] && pos[j] >= i;
        }
    }
    for(int i = 0; i < n; i++) cout << pw[res[i]] << "\n";
}