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#include "../hadamard.hpp" #define PROBLEM "https://yukicoder.me/problems/no/1240" #include <iostream> using namespace std; int main() { cin.tie(nullptr), ios::sync_with_stdio(false); int N, X; cin >> N >> X; vector<int> A(N); for (auto &x : A) { cin >> x; } const int D = 18; vector<long long> cnt(1 << D); for (auto a : A) cnt[a]++; cnt = xorconv(cnt, cnt); cnt[0] -= N; long long ret = 0; for (int d = 0; d < D; d++) { vector<long long> cntd(1 << D); int nd = 0; for (auto a : A) if (((a >> d) & 1) == 0) { cntd[a]++, nd++; } cntd = xorconv(cntd, cntd); cntd[0] -= nd; for (int i = 0; i < X; i++) { ret += (1LL << d) * (cnt[i] - cntd[i]) / 2; } } cout << ret << '\n'; }
#line 2 "convolution/hadamard.hpp" #include <cassert> #include <vector> // CUT begin // Fast Walsh-Hadamard transform and its abstraction // Tutorials: <https://codeforces.com/blog/entry/71899> // <https://csacademy.com/blog/fast-fourier-transform-and-variations-of-it> template <typename T, typename F> void abstract_fwht(std::vector<T> &seq, F f) { const int n = seq.size(); assert(__builtin_popcount(n) == 1); for (int w = 1; w < n; w *= 2) { for (int i = 0; i < n; i += w * 2) { for (int j = 0; j < w; j++) { f(seq[i + j], seq[i + j + w]); } } } } template <typename T, typename F1, typename F2> std::vector<T> bitwise_conv(std::vector<T> x, std::vector<T> y, F1 f, F2 finv) { const int n = x.size(); assert(__builtin_popcount(n) == 1); assert(x.size() == y.size()); if (x == y) { abstract_fwht(x, f), y = x; } else { abstract_fwht(x, f), abstract_fwht(y, f); } for (size_t i = 0; i < x.size(); i++) { x[i] *= y[i]; } abstract_fwht(x, finv); return x; } // bitwise xor convolution (FWHT-based) // ret[i] = \sum_j x[j] * y[i ^ j] // if T is integer, ||x||_1 * ||y||_1 * 2 < numeric_limits<T>::max() template <typename T> std::vector<T> xorconv(std::vector<T> x, std::vector<T> y) { auto f = [](T &lo, T &hi) { T c = lo + hi; hi = lo - hi, lo = c; }; auto finv = [](T &lo, T &hi) { T c = lo + hi; hi = (lo - hi) / 2, lo = c / 2; // Reconsider HEAVY complexity of division by 2 when T is ModInt }; return bitwise_conv(x, y, f, finv); } // bitwise AND conolution // ret[i] = \sum_{(j & k) == i} x[j] * y[k] template <typename T> std::vector<T> andconv(std::vector<T> x, std::vector<T> y) { return bitwise_conv( x, y, [](T &lo, T &hi) { lo += hi; }, [](T &lo, T &hi) { lo -= hi; }); } // bitwise OR convolution // ret[i] = \sum_{(j | k) == i} x[j] * y[k] template <typename T> std::vector<T> orconv(std::vector<T> x, std::vector<T> y) { return bitwise_conv( x, y, [](T &lo, T &hi) { hi += lo; }, [](T &lo, T &hi) { hi -= lo; }); } #line 2 "convolution/test/hadamard_xor.test.cpp" #define PROBLEM "https://yukicoder.me/problems/no/1240" #include <iostream> using namespace std; int main() { cin.tie(nullptr), ios::sync_with_stdio(false); int N, X; cin >> N >> X; vector<int> A(N); for (auto &x : A) { cin >> x; } const int D = 18; vector<long long> cnt(1 << D); for (auto a : A) cnt[a]++; cnt = xorconv(cnt, cnt); cnt[0] -= N; long long ret = 0; for (int d = 0; d < D; d++) { vector<long long> cntd(1 << D); int nd = 0; for (auto a : A) if (((a >> d) & 1) == 0) { cntd[a]++, nd++; } cntd = xorconv(cntd, cntd); cntd[0] -= nd; for (int i = 0; i < X; i++) { ret += (1LL << d) * (cnt[i] - cntd[i]) / 2; } } cout << ret << '\n'; }