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Diffstat (limited to 'math/transforms/all.cpp')
| -rw-r--r-- | math/transforms/all.cpp | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/math/transforms/all.cpp b/math/transforms/all.cpp new file mode 100644 index 0000000..4f4d83b --- /dev/null +++ b/math/transforms/all.cpp @@ -0,0 +1,62 @@ +/*constexpr ll mod = 998244353; @\hl{NTT only}@ +constexpr ll root = 3;*/ + +using cplx = complex<double>; + +@\hl{NTT, xor, or, and}@ +//void fft(vector<ll> &a, bool inverse = 0) { +void fft(vector<cplx>& 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; + }}*/ +} |