【模板】线性基

线性基主要用于解决子集异或问题。

#include <bits/stdc++.h>

using namespace std;

typedef long long LL;

struct linear_basis {
	vector<LL> s;
	int n, zero;
	linear_basis(int _n) {
		n = _n;
		s.resize(n + 1);
		zero = 0;
	}
	void insert(LL x) {
		for (int i = n; i >= 0; i--) {
			if (x >> i & 1) {
				if (s[i] != 0) {
					x ^= s[i];
				} else {
					s[i] = x;
					return;
				}
			}
		}
		zero = 1;
	}
	LL query_max() {
		LL ret = 0;
		for (int i = n; i >= 0; i--) {
			if (ret < (ret ^ s[i])) {
				ret ^= s[i];
			}
		}
		return ret;
	}
};

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	int n;
	cin >> n;
	linear_basis s(51);
	for (int i = 0; i < n; i++) {
		LL x;
		cin >> x;
		s.insert(x);
	}
	cout << s.query_max() << endl;
	return 0;
}