/*constexpr ll mod = 998244353; @\hl{NTT only}@ constexpr ll root = 3;*/ using cplx = complex; @\hl{NTT, xor, or, and}@ //void fft(vector &a, bool inverse = 0) { void fft(vector& a, bool inverse = 0) { int n = a.size(); for (int i = 0, j = 1; j < n - 1; ++j) { for (int k = n >> 1; k > (i ^= k); k >>= 1); if (j < i) swap(a[i], a[j]); } for (int s = 1; s < n; s *= 2) { /*ll ws = powMod(root, (mod - 1) / s >> 1, mod); @\hl{NTT only}@ if (inverse) ws = powMod(ws, mod - 2, mod);*/ double angle = PI / s * (inverse ? -1 : 1); cplx ws(cos(angle), sin(angle)); for (int j = 0; j < n; j+= 2 * s) { //ll w = 1; @\hl{NTT only}@ cplx w = 1; for (int k = 0; k < s; k++) { /*ll u = a[j + k], t = a[j + s + k] * w; @\hl{NTT only}@ t %= mod; a[j + k] = (u + t) % mod; a[j + s + k] = (u - t + mod) % mod; w *= ws; w %= mod;*/ /*ll u = a[j + k], t = a[j + s + k]; @\hl{xor only}@ a[j + k] = u + t; a[j + s + k] = u - t;*/ /*if (!inverse) { @\hl{or only}@ a[j + k] = u + t; a[j + s + k] = u; } else { a[j + k] = t; a[j + s + k] = u - t; }*/ /*if (!inverse) { @\hl{and only}@ a[j + k] = t; a[j + s + k] = u + t; } else { a[j + k] = t - u; a[j + s + k] = u; }*/ cplx u = a[j + k], t = a[j + s + k] * w; a[j + k] = u + t; a[j + s + k] = u - t; if (inverse) a[j + k] /= 2, a[j + s + k] /= 2; w *= ws; }}} /*if (inverse) { @\hl{NTT only}@ ll div = powMod(n, mod - 2, mod); for (ll i = 0; i < n; i++) { a[i] *= div; a[i] %= mod; }}*/ /*if (inverse) { @\hl{xor only}@ for (ll i = 0; i < n; i++) { a[i] /= n; }}*/ }