1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
/*constexpr ll mod = 998244353; @\hl{NTT only}@
constexpr ll root = 3;*/
using cplx = complex<double>;
//void fft(vector<ll> &a, bool inverse = 0) { @\hl{NTT, xor, or, and}@
void fft(vector<cplx>& a, bool inverse = 0) {
int n = sz(a);
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]);
}
static vector<cplx> ws(2, 1);
for (static int k = 2; k < n; k *= 2) {
ws.resize(n);
cplx w = polar(1.0, acos(-1.0) / k);
for (int i=k; i<2*k; i++) ws[i] = ws[i/2] * (i % 2 ? w : 1);
}
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);*/
for (int j = 0; j < n; j += 2 * s) {
//ll w = 1; @\hl{NTT only}@
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 = (w * ws) % 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];
t *= (inverse ? conj(ws[s + k]) : ws[s + k]);
a[j + k] = u + t;
a[j + s + k] = u - t;
if (inverse) a[j + k] /= 2, a[j + s + k] /= 2;
}}}
/*if (inverse) { @\hl{NTT only}@
ll div = powMod(n, mod - 2, mod);
for (ll i = 0; i < n; i++) {
a[i] = (a[i] * div) % mod;
}}*/
/*if (inverse) { @\hl{xor only}@
for (ll i = 0; i < n; i++) {
a[i] /= n;
}}*/
}
|
