Language: C++

/*
               _____
              /     \
              vvvvvvv  /|__/|
                 I   /O,O   |
                 I /_____   |      /|/|
                J|/^ ^ ^ \  |    /00  |    _//|
                 |^ ^ ^ ^ |W|   |/^^\ |   /oo |
                  \m___m__|_|    \m_m_|   \mm_|


 */
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>

#define fori(a, r) for(long long int a = 0; a < (r); ++a)
#define forI(a, r) for(long long int a = 1; a <= (r); ++a)

#define ff first
#define ss second
#define pll pair<ll, ll>

//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
//#pragma GCC optimize("fast-math")
//#pragma GCC optimize("unroll-loops")

using namespace std;
typedef long long int ll;
typedef long double ld;
typedef long long ull;

#define pt pair<ll, ll>
#define x first
#define y second

pt dxy[] = {{1,  0},
            {0,  1},
            {-1, 0},
            {0,  -1}};
const long long MAXN = 1 << 20, MOD = 1e9 + 7, INF = ((1ll << 60) - 1) * 2 + 1;

mt19937 random(time(0));

ll n, m;

ll ar[ll(5e5+1)];
ll pre[MAXN];

vector<ll> gap[MAXN];
vector<ll> c[MAXN];

ll temp[MAXN];

ll f(ll id){
    ll num = c[id][0];
    ll cnt = 0;

    ll ans = num;
    forI(i, gap[id].size()){
        ll val = num * c[id][i] % MOD * gap[id][i - 1] % MOD + cnt * c[id][i] % MOD;

        ans += val + c[id][i];
        ans %= MOD;

        cnt += num * gap[id][i - 1];
        num = val;
    }
    return ans;
}

ll pw(ll a, ll b){
    if(b == 0) return 1;
    ll e = pw(a, b >> 1);
    return b & 1 ? e * e % MOD * a % MOD : e * e % MOD;
}

void solve() {
    cin >> n;
    ll xr = 0;
    vector<ll> gc;
    ll block_num = 0;
    forI(i, n){
        cin >> ar[i];
        xr ^= ar[i];
        ar[i] = xr;

        ++temp[xr];
        if(temp[xr] == 1) gc.push_back(xr);

        if(xr == 0){
            ++block_num;
            for(ll e: gc){
                c[e].push_back(temp[e]);
                temp[e] = 0;

                if(pre[e])
                    gap[e].push_back(block_num - pre[e]);
                pre[e] = block_num;
            }
            gc.clear();
        }
    }


    if(xr){
        ll cnt = 0;
        fori(i, n){
            cnt += (cnt & 1 && !ar[i]) || (!(cnt & 1) && ar[i] == xr);
        }
        //fibonacci?
        ll a = 0;
        ll b = 1;
        fori(i, cnt - 1){
            a += b;
            swap(a, b);
        }
        cout << b;
        return;
    }


    ll ans = pw(2, block_num - 1);
    fori(i, MAXN){
        if(pre[i]){
            //delete?
            if(i == 0) continue;


            ans += f(i);
            ans %= MOD;
        }
    }
    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
#define DEBUG0
#ifdef DEBUG
    freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
#endif
    solve();
    //another();
}

Compiler output:
a.cc:107:16: error: 'std::mt19937 random' redeclared as different kind of entity
  107 | mt19937 random(time(0));
      |                ^~~~
In file included from /usr/include/c++/14/bits/std_abs.h:38,
                 from /usr/include/c++/14/cmath:49,
                 from a.cc:19:
/usr/include/stdlib.h:521:17: note: previous declaration 'long int random()'
  521 | extern long int random (void) __THROW;
      |                 ^~~~~~