多项式全家桶
多项式全家桶
整理各种多项式函数, 其实只不过是一部分而已,写出来方便复习吧(虽然似乎已经快要退役了呢) ## 快速傅里叶变换 fft
快速数论变换 ntt
离散傅里叶变换
dft(poly& f)
类似fft,需要在 \(\mathbb{F}_P\)下找到合适的\(n\)次单位根\(w_n\) 根据数论知识,\(n\)次单位根存在当且仅当 \(n \mid \phi(P)\), 即 \(n | (P - 1)\) 而由于我们需要做蝶形变换,因此 \(n\) 是 \(2\) 的高次幂,因此我们希望 \(P\) 可以写成 : \[P = q\cdot 2^k + 1\] 这样的形式,且\(k\)尽可能大,以方便我们可以对更长的数组做ntt. \(998244353\)是一个合适的数, 其中一个原根 \(g = 3\) 知道原根后,\(n\)次单位根\(\omega_n\)是易求的: \[\omega_n = g^{\frac{P - 1}{n}}\] 式子右边很容易验证符合 \(w_n\) 的性质. 离散傅里叶变换公式: \[F_k = f(\omega^k) = \sum_{j = 0}^{n - 1} w^{jk}f_j \] 于是仿照fft做蝶形变换即可
离散傅里叶逆变换
idft(poly& f)
ntt实现的idft可以使用一点技巧 fft中,实现逆变换是使用\(\omega_{n}^{-1}\),这里也可以这么做,不过也可以利用数论知识换一下形式:
\[\begin{align*}
f_k = F(\omega^{-k}) &= \sum_{j = 0}^{n - 1} w^{-jk}F_j \\
&= \sum_{j = 0}^{n - 1} w^{(n-j)k}F_j \\
&= \sum_{j = 0}^{n - 1} w^{jk}F_{n - j \bmod n}
\end{align*}\] 因此我们可以对于\(j \in
[1, n - 1]\), 我们翻转这一段,而\(n - 0
= 0 \pmod n\),不变,然后做一次dft. 于是写出来一个很像 1-base
但是完全不是这么回事的代码: 1
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11void idft(vector<int>& f)
{
int n = f.size();
int invn = inv(n);
reverse(f.begin() + 1, f.end());
dft(f);
for(int i = 0;i < n;i++){
f[i] = 1ll * f[i] * invn % P;
}
return;
}
原理
为什么fft可以把卷积变成点积?甚至这一策略可以平移到\(\mathbb{F}_P\)? 其实可以只关注我们利用到的性质,在最小条件下进行推理。 给定一个交换环\(R\), \(\omega \in R\), \(\operatorname{ord}(\omega) = n\) 定义\(R^n\)上的dft(没有归一化): \[\hat{a}(k) = \sum_{j = 0}^{n - 1}a_j w^{jk}, k = 0,1,\dots,n-1\] 定义\(R^n\)上的循环卷积: \[(a * b)_t = \sum_{j = 0}^{n - 1} a_j b_{t - j \bmod n}\]
于是可以证明: \[\widehat{a*b} = \hat{a} * \hat{b}\]
给出一个证明: 令\(c = a * b\)有: \[\begin{align*} \hat{c}_k &= \sum_{j = 0}^{n - 1} c_j w^{jk} \\ &= \sum_{j = 0}^{n - 1} \sum_{t = 0}^{n - 1} (a_t b_{j - t \bmod n}) w^{jk}\\ &= \sum_{t = 0} a_t \sum_{j = 0}^{n - 1} b_{j - t \bmod n} w^{jk} \\ &= \sum_{t = 0} a_t \sum_{s = j - t \bmod n, s = 0}^{n - 1} b_{s} w^{(s + t)k} \\ &= \sum_{t = 0} a_t w^{tk} \sum_{s = 0}b_{s} w^{sk} \\ &= \hat{a}_k \hat{b}_k \end{align*}\]
所以这个策略在 \(C\), \(\mathbb{F}_P\)上均有用 有一个平时注意不到的点是:我们实际上实现的是循环卷积,而非普通卷积,这个性质在一些特殊的场合可以发挥作用。 也就是说,我们实现的多项式乘法不是在\(\mathbb{F}_P^n\)上,而是在\(\mathbb{F}_P[x]/(x^n - 1)\)这个商环上。 本质上,dft是商环\(R[x]/(x^n - 1)\)到直积\(R^n\)的同构。
截断 truck(int m)
从第\(m\)位开始截断, 形式化即\(\mod x^m\)
右移 shift(int m)
移位函数,在左边插入若干个\(0\),或者截断一些位 形式化即 \(x^m f\) 去掉负数项
翻转 rev()
从最高位开始翻转多项式 形式化来说,相当于\(f^R = x^{\operatorname{deg}(f)} f(\frac{1}{x})\)
形式导数 deriv()
求形式导数
形式不定积分 integr()
求形式积分
多项式乘法逆 inv(int m)
使用多项式牛顿迭代: \[\begin{align*} Af &= 1\\ A - \frac{1}{f} &= 0\\ \rightarrow f_{2n} = f_n - \frac{A - f_n^{-1}}{-f_n^{-2}} &= f_n(2 + Af_n) \end{align*}\] 从\(f_0 = A_0^{-1}\)开始迭代即可 因此要求常数位非\(0\) 另外一种解释是可以看作\(\mod x^\infty\) 下求逆,那么存在逆元当且仅当\(\gcd(f, x^\infty) = 1\),即\(f\)常数项不为\(0\).
多项式对数函数
log(int m)
\[\begin{align*} f &= \ln A(x) \\ f'&= \frac{1}{A(x)} \\ f &= \int \frac{1}{A(x)} \end{align*}\] 求逆再积分回去即可 根据定义,常数项必须是1
多项式指数函数
exp(int m)
有两种方法,\(O(n\log n)\) 的牛顿迭代 和 \(O(n \log^2 n)\) 的半在线卷积 实际上半在线卷积要比牛顿迭代快不少
牛顿迭代
根据初始条件写出迭代式: \[\begin{align*} f &= e^{A}\\ A - \ln f &= 0\\ \rightarrow f_{2n} = f_n - \frac{A - \ln f_n}{-f_n^{-1}} &= f_n(1 + A - \ln f_n) \end{align*}\] 从\(f_0 = 1\)开始迭代即可 根据主定理,时间复杂度为\(O(n\log n)\)
半在线卷积
\[\begin{align*} F &= e^{G}\\ \ln F &= G\\ \frac{F'}{F} &= G'\\ F' &= FG' \\ \rightarrow nf_{n} &= \sum_{k = 0}^{n - 1} kg_k f_{n - k} \end{align*}\] (对求导算子对系数的影响要熟练) 用半在线卷积实现即可
多项式快速幂
pow(int n, int k)
如果常数项为\(1\),直接\(\ln + \exp\)即可处理 常数项非\(1\),那么不能直接取对数函数 首先,先去掉前面为\(0\)的项,相当于提一个因子\(x^i\) 其次,如果处理后的常数项非\(1\),那么再提一个常数因子\(v\)即可 求解多项式快速幂后,乘上 \(v^k\),补上 \(ki\) 个 \(0\) 即可
在\(k\)相当大的时候需要注意的一些点: 实际上,可以证明: \[f(x)^k \equiv f(x)^{k \bmod P} \mod x^P\] 这个可以展开\(\exp\)系数得到这个结论 然而,在我们上面的处理中,有一步是乘上 \(v^k\),显然这里的 \(k\) 必须模 \(\phi(P) = P - 1\) 注意这两个地方的模数是不一样的! 此外,我们实际上要补\(ki\) 而非 \((k \bmod P)i\) 个 \(0\), 所以当 \(k \equiv 0 \pmod P\)时,要特判一下,避免没有补应该补的 \(0\) 导致错误。
多项式开根 sqrt(int m)
使用多项式牛顿迭代 \[\begin{align*} f &= \sqrt{A}\\ A - f^2 &= 0\\ \rightarrow f_{2n} = f_n - \frac{A - f_n^2}{2f_n} &= \frac{1}{2 f_n}(A + f_n) \end{align*}\] 从\(f_0 = \sqrt{A_0}\)开始迭代即可 这部分时间复杂度 \(O(n \log n)\) 这里要求 \(A_0\) 是\(\mod P\) 的二次剩余 可以用Cipolla算法求二次剩余 不过也可以用慢一些的算法,毕竟主要开销还是牛顿迭代. 选一个原根\(g\),用bsgs算出阶 \(ord\), 那么\(g^{\frac{ord}{2}}\)就是一个平方根. 这样的话,时间复杂度是\(O(\sqrt P)\)
多项式除法 / & 取余
%
除朴素除法外,其实有更快计算多项式带余除法的方法. 设\[A(x) = Q(x)B(x) + R(x)\] 其中 \(\operatorname{deg}(A) = n\), \(\operatorname{deg}(B) = m\) 可得:\(\operatorname{deg}(Q) = n - m\), \(\operatorname{deg}(R) < m\) 代入\(\frac{1}{x}\) \[\begin{align*} A(\frac{1}{x}) &= Q(\frac{1}{x})B(\frac{1}{x}) + R(\frac{1}{x}) \\ x^n A(\frac{1}{x}) &= x^{n - m}Q(\frac{1}{x}) x^m B(\frac{1}{x}) + x^n R(\frac{1}{x})\\ A^R(x) &= Q^R(x) B^R(x) + x^{n - \operatorname{deg}(R)} R^R(x) \end{align*}\] 由于\(n - \operatorname{deg}(R) > n - m\) 所以等式两边的小于等于 \(n - m\) 次项与 \(R^R(x)\)无关, 因为它乘上了\(x^{n - \operatorname{deg}(R)}\)这个系数 即 \[A^R(x) = Q^R(x) B^R(x) \mod x^{n - m + 1}\\ Q^R(x) = \frac{A^R(x)}{B^R(x)} \mod x^{n - m + 1}\] 于是通过一次多项式求逆和多项式乘法就可以算出\(Q(x)\),而知道\(Q(x)\)后,\(R(x)\)就很容易计算了。
多项式多点求值
eval(vector<int>x)
其实就是使用分治去求解,不过可以通过一些科技去显著降低常数 ### 朴素方法 求解\(f(x_0),f(x_1) \dots f(x_{n - 1})\),设 \(m = \lfloor\frac{n}{2}\rfloor\), \(M_{l,r} = \prod_{i = l}^r (x-x_i)\) 将\(f(x)\) 拆成两部分: \(f(x) = M_{0,m}(x)P(x) + R(x)\) 显然左边这部分对于\(x = x_0, x_1,\dots,x_m\)的贡献均为 \(0\) 于是我们可以递归下去,对 \(R\) 求解。 这里需要一次多项式取模,复杂度\(O(n \log n)\),不过常数偏大。 而对于\(x = x_{m + 1}, \dots , x_{n - 1}\), 我们模上 \(M_{m + 1, n - 1}\) 同样递归求解即可。 构建 \(M\) 我们使用分治ntt,时间复杂度是 \(O(n \log^2 n)\) 于是最后的时间复杂度 \(T(n) = O(n \log n) + 2 T(\frac{n}{2}) \Rightarrow T(n) = O(n \log^2 n)\) 实际上,很容易注意到一个点: \[f(x_i) = f(x) \bmod (x - x_i)\] 我们上述做法不过是在分治地取模而已,类似于分治ntt(虽然这个是自顶向下的)
Laurent 级数 / 转置原理(特勒根原理)
这里给出一个形式洛朗级数的式子 \[f(v) = [x^0]\frac{f(x^{-1})}{1 - vx}\] 这是好验证的,展开分母,\(x^0\)的系数显然是: \[\sum_{i = 0}^{\infty} f_i v^i = f(v)\] 原理推导完毕,我们希望对于每一个 \(v = x_i\) 计算出上式。 于是还是考虑分治: 设\(M_{l, r} = \prod_{i = l} ^ r (1 - x_i x)\) 我们从\(\frac{f(x^{-1})}{M_{0, n - 1}}\)开始递归, 从区间 \([l, r]\) 求解区间 \([l, m]\) 时,乘上\(M_{m+1,r}\)即可。 此时我们每次递归下去仅需要一次多项式乘法,相比多项式取模常数大大减小。
不过需要注意的是:这里的乘法不是一般的矩阵乘法!因为我们维护的是一个以\(x^{-1}\)为变量的多项式,所以这里实际上是差卷积,也可以从转置原理的角度理解为转置乘法。 因为我们希望最终得到\(x^0\)的系数,于是如果这个区间还有\(k\)个点值需要求解,我们将多项式截断到\(x^{-k}\)即可 递归过程的时间复杂度是类似的,为\(O(n \log^2 n)\), 加上构建 \(M\) 的时间复杂度 \(O(n \log^2 n)\) 和一次多项式求逆 \(O(n \log n)\), 总时间复杂度\(O(n \log^2 n)\)
当然,这个做法可以从朴素做法的转置这个角度来理解,不过可能需要对线性变换的理解到达一定程度。
多项式快速插值
lagrange(vector<int>x, vector<int>y)
设\(M(x) = \prod_{i = 0}^n (x - x_i)\) 考虑lagrange插值公式: \[\begin{align*} f(x) &= \sum_{i = 0}^{n} y_i \prod_{j \neq i} \frac{x - x_j}{x_i - x_j}\\ \end{align*}\] 对于右边式子的分母,使用洛必达法则,有: \[\prod_{j \neq i} \frac{1}{x_i - x_j} = \lim_{x\rightarrow x_i} \frac{x - x_i}{\prod_j x - x_j} = \lim_{x\rightarrow x_i} \frac{x - x_i}{M(x)} = \frac{1}{M'(x_i)}\] 于是 \[\begin{align*} f(x) &= \sum_{i = 0}^{n} \frac{y_i}{M'(x_i)} \prod_{j \neq i} x - x_j\\ &= \sum_{i = 0}^{n} v_i \prod_{j \neq i} x - x_j \end{align*}\] 分治ntt算出\(M(x)\), 用多点求值求出\(M'(x_i)\), 进一步求出 \(v_i\) 剩下的问题就是怎么计算上面那个和式 还是考虑分治,假设分治到区间\([l, r]\)有结果 \[\begin{align*} f_{l, r} &= \sum_{i = l}^r v_i\prod_{j \neq i, l \leq j \leq r}x - x_j \\ &= f_{l, m} \prod_{j = m + 1}^{r}x - x_j + f_{m + 1, r} \prod_{j = l}^{m}x - x_j \end{align*}\] 前面分治ntt计算\(M(x)\)时预处理好连乘积多项式, 按照上式分治递归下去即可。 时间复杂度为\(O(n \log^2 n)\)
多项式平移
taylorShift(Poly f, int c)
将系数表示的多项式\(f(x)\) 变为 \(f(x + c)\) \[\begin{align*} f(x + c) &= \sum_i f_i (x + c)^i\\ &= \sum_{i = 0}^{n} f_i \sum_{j = 0}^i \binom{i}{j} x^j c^{i - j}\\ &= \sum_{i = 0}^{n} i! f_i \sum_{j = 0}^i \frac{x^j}{j!} \frac{c^{i - j}}{(i - j)!}\\ &= \sum_{j = 0}^{n} \frac{x^j}{j!} \sum_{i = j}^{n} i! f_i \frac{c^{i - j}}{(i - j)!}\\ \end{align*}\] 显然这是一个差卷积的形式,直接是实现即可。 时间复杂度\(O(n \log n)\)
多项式连续点值平移
valueShift(poly f, int c)
连续点值表示的多项式\(f(0),f(1)\dots,f(n)\),计算出\(f(c),f(c + 1),\dots,f(c + n)\), \(c > n\) 考虑Lagrange插值 \[\begin{align*} f(x)&= \sum_{i = 0}^{n} f(i) \prod_{j \neq i}\frac{x - j}{i - j}\\ &= \sum_{i = 0}^{n} f(i) \frac{(-1)^{n - i} x^{\underline{n}}}{(x - i)i!(n - i)!}\\ &= x^{\underline{n + 1}}\sum_{i = 0}^{n} \frac{(-1)^{n - i}f(i)}{i!(n - i)!} \frac{1}{(x - i)}\\ \frac{f(x)}{x^{\underline{n + 1}}} &= \sum_{i = 0}^{n} \frac{(-1)^{n - i}f(i)}{i!(n - i)!} \frac{1}{(x - i)}\\ \end{align*}\] 我们得到了一个恒等式, 而我们希望将左边代入\(f(x + t)\)时通过右式求值(实际上是通过分式线性插值)。 此时右式是一个卷积形式, 我们不妨设 \[A(x) = \sum_{i = 0}^n\frac{(-1)^{n - i}f(i)}{i!(n - i)!}x^i\\ B(x) = \sum_{i}\frac{1}{c + i - n}x^i\] 有: \[\begin{align*} [x^{n + t}]A(x)B(x) &= \sum_{i = 0}^{n}\frac{(-1)^{n - i}f(i)}{i!(n - i)!} \frac{1}{c + (n + t - i) - n}\\ &= \sum_{i = 0}^{n}\frac{(-1)^{n - i}f(i)}{i!(n - i)!} \frac{1}{c + t - i}\\ &= \frac{f(c + t)}{(c + t)^{\underline{n + 1}}} \\ f(c + t) &= (c + t)^{\underline{n + 1}}[x^{n + t}]A(x)B(x) \end{align*}\] 需要注意的是\(B\)序列更长一些(\(2n + 1\))。 我们通过\(O(n)\)预处理下降幂, 时间复杂度由卷积决定, 为\(O(n \log n)\)
常系数齐次线性递推
Kitamasa/Fiduccia
算法
kitamasa(vector<int>a, vector<int>c, i64 n)
Todo
表示为有理函数
+ Bostan–Mori 算法 bostanMori(poly p, poly q, poly n)
linearRecurrence(poly a, poly c, i64 n)
Todo
最小多项式
Berlekamp Massey算法 berlekampMassey
Todo
多项式复合
comp(poly g, int m)
\(h(x) = f(g(x)) \equiv [y^{0}] \frac{f(y^{-1})}{1 - yg(x)} \pmod {x^m}\) Todo
多项式复合逆
revert(int m)
Todo
代码
附上最后的整体代码 1
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using i64 = long long;
using ll = long long;
using uint = unsigned int;
using ull = unsigned long long;
using namespace std;
//polys.cpp Create time : 2026.01.13 22:21
constexpr int P = 998244353;
constexpr int G = 3;
int power(int a, int p)
{
int res = 1;
while(p){
if(p & 1)res = 1ll * res * a % P;
a = 1ll * a * a % P;
p >>= 1;
}
return res;
}
int power(int a, int p, int M)
{
int res = 1;
while(p){
if(p & 1)res = 1ll * res * a % M;
a = 1ll * a * a % M;
p >>= 1;
}
return res;
}
int inv(int a)
{
return power(a, P - 2);
}
struct Comb {
int n;
std::vector<int> _fac;
std::vector<int> _invfac;
std::vector<int> _inv;
Comb() : n{0}, _fac{1}, _invfac{1}, _inv{0} {}
Comb(int n) : Comb() {
init(n);
}
void init(int m) {
if (m <= n) return;
_fac.resize(m + 1);
_invfac.resize(m + 1);
_inv.resize(m + 1);
for (int i = n + 1; i <= m; i++) {
_fac[i] = 1ll * _fac[i - 1] * i % P;
}
_invfac[m] = power(_fac[m], P - 2);
for (int i = m; i > n; i--) {
_invfac[i - 1] = 1ll * _invfac[i] * i % P;
_inv[i] = 1ll * _invfac[i] * _fac[i - 1] % P;
}
n = m;
}
int fac(int m) {
if (m > n) init(2 * m);
return _fac[m];
}
int invfac(int m) {
if (m > n) init(2 * m);
return _invfac[m];
}
int inv(int m) {
if (m > n) init(2 * m);
return _inv[m];
}
int binom(int n, int m) {
if (n < m || m < 0) return 0;
return fac(n) * invfac(m) * invfac(n - m);
}
} comb;
int bsgs(int a, int b, int p)
{
a %= p;
b %= p;
if(p == 1) return 0;
if(b == 1) return 0;
int sq = ceil(sqrt(p));
unordered_map<int,int>mp;
int x = 1;
for(int i = 0;i <= sq;i++){
mp[1ll * x * b % p] = i;
x = 1ll * x * a % p;
}
int asq = power(a, sq, p);
int y = asq;
for(int i = 1;i <= sq;i++){
if(mp.find(y) != mp.end()){
return i * sq - mp[y];
}
y = 1ll * y * asq % p;
}
return -1;
}
int Fsqrt(int x)
{
int p = bsgs(G, x, P);
return power(G, p / 2);
}
constexpr int Q = 23; //998244353 = K 2^Q + 1
constexpr int MAX_LEN = 22;
array<int, 1 << MAX_LEN> omega()
{
array<int, 1 << MAX_LEN> res;
res.fill(1);
for (int i = 1; i <= (1 << MAX_LEN - 1); i <<= 1) {
int wi = power(G, (P - 1) / (i * 2));
for (int j = 1; j < i; j++) {
res[i + j] = 1ll * res[i + j - 1] * wi % P;
}
}
return res;
}
const array<int, 1 << MAX_LEN> W = omega();
void dft(vector<int>& f)
{
int n = (int)f.size();
// DIF: input natural order, output bit-reversed order
for (int k = n >> 1; k; k >>= 1) {
for (int i = 0; i < n; i += k << 1) {
for (int j = 0; j < k; j++) {
int x = f[i + j];
int y = f[i + j + k];
// f[i+j] = x + y
int s = x + y;
if (s >= P) s -= P;
f[i + j] = s;
// f[i+j+k] = (x - y) * W[k+j]
int d = x - y;
if (d < 0) d += P;
f[i + j + k] = 1ll * d * W[k + j] % P;
}
}
}
return;
}
void idft(vector<int>& f)
{
int n = (int)f.size();
int invn = inv(n);
// IDIT: take bit-reversed order (from DIF), output natural order
for (int k = 1; k < n; k <<= 1) {
for (int i = 0; i < n; i += k << 1) {
for (int j = 0; j < k; j++) {
int x = f[i + j];
int y = 1ll * f[i + j + k] * W[k + j] % P;
int s = x + y;
if (s >= P) s -= P;
int d = x - y;
if (d < 0) d += P;
f[i + j] = s;
f[i + j + k] = d;
}
}
}
// scale by 1/n
for (int i = 0; i < n; i++) {
f[i] = 1ll * f[i] * invn % P;
}
// reverse except f[0] (invNTT trick with +roots)
reverse(f.begin() + 1, f.end());
return;
}
class poly : public vector<int>
{
public:
poly() : vector<int>(){}
template<class F>
explicit poly(int n, F f) : vector<int>(n)
{
for(int i = 0;i < n;i++){
(*this)[i] = f(i);
}
}
template<class InputIt, class = std::_RequireInputIter<InputIt>>
explicit poly(InputIt first, InputIt last) : vector<int>(first, last) {}
explicit poly(int n, int val) : vector<int>(n, val){}
explicit poly(int n) : vector<int>(n){}
explicit poly(const vector<int> &a) : vector<int>(a) {}
poly(const std::initializer_list<int> &a) : vector<int>(a){}
friend poly operator+(const poly &a, const poly &b) {
poly res(std::max(a.size(), b.size()));
for (int i = 0; i < a.size(); i++) {
res[i] = a[i];
}
for (int i = 0; i < b.size(); i++) {
res[i] = res[i] + b[i];
if(res[i] >= P)res[i] -= P;
}
return res;
}
friend poly operator-(const poly &a, const poly &b) {
poly res(std::max(a.size(), b.size()));
for (int i = 0; i < a.size(); i++) {
res[i] = a[i];
}
for (int i = 0; i < b.size(); i++) {
res[i] = res[i] - b[i];
if(res[i] < 0)res[i] += P;
}
return res;
}
friend poly operator-(const poly &a) {
std::vector<int> res(a.size());
for (int i = 0; i < int(res.size()); i++) {
res[i] = a[i] ? P - a[i] : 0;
}
return poly(res);
}
friend poly operator*(int a, poly b) {
a = (a % P + P) % P;
for (int i = 0; i < int(b.size()); i++) {
b[i] = 1ll * b[i] * a % P;
}
return b;
}
friend poly operator*(poly a, int b) {
b = (b % P + P) % P;
for (int i = 0; i < int(a.size()); i++) {
a[i] = 1ll * a[i] * b % P;
}
return a;
}
friend poly operator/(poly a, int b) {
b = (b % P + P) % P;
int invb = power(b, P - 2);
for (int i = 0; i < int(a.size()); i++) {
a[i] = 1ll * a[i] * invb % P;
}
return a;
}
friend poly operator/(const poly &a, const poly &b) {
if(a.size() < b.size())return poly();
int k = a.size() - b.size() + 1;
return (a.rev().trunc(k) * b.rev().inv(k).trunc(k)).trunc(k).rev();
}
friend poly operator%(const poly &a, const poly &b) {
return (a - a / b * b).trunc(min(a.size(), b.size() - 1));
}
poly &operator+=(poly b) {
return (*this) = (*this) + b;
}
poly &operator-=(poly b) {
return (*this) = (*this) - b;
}
poly &operator*=(poly b) {
return (*this) = (*this) * b;
}
poly &operator*=(int b) {
return (*this) = (*this) * b;
}
poly &operator/=(int b) {
return (*this) = (*this) / b;
}
friend poly operator*(poly a, poly b) {
if (a.size() == 0 || b.size() == 0) {
return poly();
}
if (a.size() < b.size()) {
std::swap(a, b);
}
int n = 1, tot = a.size() + b.size() - 1;
while (n < tot) {
n *= 2;
}
if (((P - 1) & (n - 1)) != 0 || b.size() < 128) {
poly c(a.size() + b.size() - 1);
for (int i = 0; i < a.size(); i++) {
for (int j = 0; j < b.size(); j++) {
c[i + j] = (c[i + j] + 1ll * a[i] * b[j]) % P;
}
}
return c;
}
a.resize(n);
b.resize(n);
dft(a);
dft(b);
for (int i = 0; i < n; ++i) {
a[i] = 1ll * a[i] * b[i] % P;
}
idft(a);
a.resize(tot);
return a;
}
poly shift(int k) const {
if (k >= 0) {
auto b = *this;
b.insert(b.begin(), k, 0);
return b;
} else if (this->size() <= -k) {
return poly();
} else {
return poly(this->begin() + (-k), this->end());
}
}
poly trunc(int k) const {
poly f = *this;
f.resize(k);
return f;
}
poly deriv() const {
if (this->empty()) {
return poly();
}
poly res(this->size() - 1);
for (int i = 0; i < this->size() - 1; ++i) {
res[i] = 1ll * (i + 1) * (*this)[i + 1] % P;
}
return res;
}
poly integr() const {
poly res(this->size() + 1);
comb.init(this->size() + 1);
for (int i = 0; i < this->size(); ++i) {
res[i + 1] = 1ll * (*this)[i] * comb.inv(i + 1) % P;
}
return res;
}
poly rev() const{
if(this->empty()){
return poly();
}
poly res = *this;
while(!res.empty() && res.back() == 0)res.pop_back();
reverse(res.begin(),res.end());
return res;
}
poly inv(int m) const {
poly x{power((*this)[0], P - 2)};
int k = 1;
while (k < m) {
k *= 2;
x = (x * (poly{2} - trunc(k) * x)).trunc(k);
}
return x.trunc(m);
}
poly log(int m) const {
return (deriv() * inv(m)).integr().trunc(m);
}
poly exp(int m) const {
poly x{1};
int k = 1;
while (k < m) {
k *= 2;
x = (x * (poly{1} - x.log(k) + trunc(k))).trunc(k);
}
return x.trunc(m);
}
poly exp2(int m) const {
poly f(m), h = deriv();
h.resize(m);
f[0] = 1;
// fn = 1/n(\sum h_k f_{n - 1 - k})
auto cdq = [&](auto&&self, int l ,int r)->void
{
if(l == r){
if(l == 0)return;
f[l] = 1ll * f[l] * comb.inv(l) % P;
return;
}
int m = l + r >> 1;
self(self, l, m);
poly a(m - l + 1),b(r - l);
for(int i = 0;i <= m - l;i++){
a[i] = f[i + l];
}
for(int i = 0;i < r - l;i++){
b[i] = h[i];
}
auto c = a * b;
for(int i = 0;i < r - m;i++){
f[m + i + 1] = f[m + i + 1] + c[i + m - l];
if(f[m + i + 1] >= P)f[m + i + 1] -= P;
}
self(self, m + 1, r);
return;
};
cdq(cdq, 0, m - 1);
return f;
}
poly pow(int k, int m) const {
int i = 0;
while (i < this->size() && (*this)[i] == 0) {
i++;
}
if (i == this->size() || 1LL * i * k >= m) {
return poly(m);
}
int v = (*this)[i];
auto f = shift(-i) * power(v, P - 2);
return ((f.log(m - i * k) * k).exp2(m - i * k).shift(i * k)) * power(v, k);
}
poly pow(int k, int kmodphiP,int big, int m) const {
int i = 0;
while (i < this->size() && (*this)[i] == 0) {
i++;
}
if (i == this->size() || 1LL * i * k >= m) {
return poly(m);
}
if(big && i > 0)return poly(m);//x^{big number} f(x)^{k}
int v = (*this)[i];
auto f = shift(-i) * power(v, P - 2);
return ((f.log(m - i * k) * k).exp2(m - i * k).shift(i * k)) * power(v, kmodphiP);
}
poly sqrt(int m) const {
poly x{Fsqrt((*this)[0])};
int k = 1;
while (k < m) {
k *= 2;
x = (x + (trunc(k) * x.inv(k)).trunc(k)) * power(2, P - 2);
}
return x.trunc(m);
}
poly mulT(poly b) const {
if (b.size() == 0) {
return poly();
}
int n = b.size();
std::reverse(b.begin(), b.end());
return ((*this) * b).shift(-(n - 1));
}
vector<int> eval(vector<int> x)const
{
if(this->size() == 0){
return vector<int>(x.size(), 0);
}
if(x.size() == 0){
return vector<int>(0);
}
int n = max(x.size(), this->size()); // !!!
x.resize(n);
for(int i = 0;i < n;i++){ //norm P - x[i]
if(x[i] <= 0)x[i] += P;
if(x[i] > P)x[i] -= P;
}
vector<poly>m(n * 4);//segtree build Q(x)
auto build = [&](auto&&self, int l, int r, int p)->void
{
if(l == r){
m[p] = poly{1, P - x[l]};
return;
}
int mid = l + r >> 1;
self(self, l, mid , p * 2);
self(self, mid + 1, r, p * 2 + 1);
m[p] = m[p * 2] * m[p * 2 + 1];
return;
};
build(build, 0, n - 1, 1);
vector<int>ans(n);
auto work = [&](auto&&self,const poly &f, int l, int r, int p)->void
{
if(l == r){
ans[l] = f[0];
return;
}
int mid = l + r >> 1;
self(self, f.mulT(m[p * 2 + 1]).trunc(mid - l + 1), l, mid, p * 2);
self(self, f.mulT(m[p * 2]).trunc(r - mid), mid + 1, r, p * 2 + 1);
return;
};
work(work, mulT(m[1].inv(n)).trunc(n), 0, n - 1, 1);
return ans;
}
};
poly lagrange(vector<int>x, vector<int>y)
{
assert(x.size() == y.size());
if(x.size() == 0)return poly();
int n = x.size();
for(int i = 0;i < n;i++){ //norm P - x[i]
if(x[i] <= 0)x[i] += P;
if(x[i] > P)x[i] -= P;
}
for(int i = 0;i < n;i++){ //norm P - x[i]
if(y[i] <= 0)y[i] += P;
if(y[i] > P)y[i] -= P;
}
vector<poly>m(n * 4);//segtree build Q(x)
auto build = [&](auto&&self, int l, int r, int p)->void
{
if(l == r){
m[p] = poly{P - x[l], 1};
return;
}
int mid = l + r >> 1;
self(self, l, mid , p * 2);
self(self, mid + 1, r, p * 2 + 1);
m[p] = m[p * 2] * m[p * 2 + 1];
return;
};
build(build, 0, n - 1, 1);
auto dM = m[1].deriv();
auto v = dM.eval(x);
for(int i = 0;i < n;i++){
v[i] = 1ll * power(v[i], P - 2) * y[i] % P;
}
auto work = [&](auto&&self, int l, int r, int p)->poly
{
if(l == r){
return poly{v[l]};
}
int mid = l + r >> 1;
return m[p * 2] * self(self, mid + 1, r, p * 2 + 1) + m[p * 2 + 1] * self(self, l, mid, p * 2);
};
return work(work, 0, n - 1, 1);
}
vector<int> valueShift(const vector<int>&v, int c)
{
int n = v.size() - 1;
poly a(n + 1),b(n * 2 + 1);
//fac, invfac
vector<int>fac(n + 1), invfac(n + 1);
vector<int>cfac(n * 2 + 2), invcfac(n + 1); // base c - n - 1
int cbase = c - n - 1;
cfac[0] = fac[0] = 1;
for(int i = 1;i <= n;i++){
fac[i] = 1ll * fac[i - 1] * i % P;
}
invfac[n] = inv(fac[n]);
for(int i = n - 1;i >= 0;i--){
invfac[i] = 1ll * invfac[i + 1] * (i + 1) % P;
}
for(int i = 1;i <= n * 2 + 1;i++){
cfac[i] = 1ll * cfac[i - 1] * (i + cbase) % P;
}
invcfac[n] = inv(cfac[n]);
for(int i = n - 1;i >= 0;i--){
invcfac[i] = 1ll * invcfac[i + 1] * (i + 1 + cbase) % P;
}
for(int i = 0;i <= n;i++){
a[i] = 1ll * v[i] * invfac[i] % P * invfac[n - i] % P;
if((n - i) % 2 == 1)a[i] = a[i] ? P - a[i] : 0;
}
for(int i = 0;i <= n * 2;i++){
b[i] = inv(c - n + i);
}
auto h = a * b;
vector<int>vc(n + 1);
for(int i = 0;i <= n;i++){
vc[i] = 1ll * h[i + n] * cfac[n + i + 1] % P * invcfac[i] % P;
}
return vc;
}
poly taylorShift(poly& f, int c)
{
int n = f.size();
poly a(n), b(n * 2 - 1);
vector<int>fac(n + 1), invfac(n + 1);
fac[0] = 1;
for(int i = 1;i <= n;i++){
fac[i] = 1ll * fac[i - 1] * i % P;
}
invfac[n] = inv(fac[n]);
for(int i = n - 1;i >= 0;i--){
invfac[i] = 1ll * invfac[i + 1] * (i + 1) % P;
}
for(int i = 0;i < n;i++){
a[i] = 1ll * f[i] * fac[i] % P;
}
int cp = 1;
for(int i = 0;i < n;i++){
b[i] = 1ll * cp * invfac[i] % P;
cp = 1ll * cp * c % P;
}
auto g = a.mulT(b);
poly res(n);
for(int i = 0;i < n;i++){
res[i] = 1ll * g[i] * invfac[i] % P;
}
return res;
}
int bostanMori(poly& p, poly& q, i64 n) // calc [x^n] P(x)/Q(x)
{
int k = q.size() - 1;
while (n > 0) {
poly nq = q;
for (int i = 1; i <= k; i += 2) {
nq[i] = -nq[i];
if(nq[i] < 0)nq[i] += P;
}
auto np = p * nq;
nq = q * nq;
for (int i = 0; i < k; i++) {
p[i] = np[i * 2 + n % 2];
}
for (int i = 0; i <= k; i++) {
q[i] = nq[i * 2];
}
n /= 2;
}
return 1ll * p[0] * inv(q[0]) % P;
}
int linearRecurrence(poly a, poly c, i64 n) //a_0 ... a_{k - 1} , c_1 ... c_k
{
assert(a.size() + 1 == c.size());
assert(c[0] == 0 || c[0] == P - 1);
c[0] = -1;
int k = a.size();
poly p = (a * (-c)).trunc(k), q = -c;
return bostanMori(p, q, n);
}
poly berlekampMassey(const vector<int>& s) {
if (s.empty()) {
return poly{P - 1};
}
poly C{1}; // c[0] = 1
poly B{1};
int L = 0;
int m = 1; // dist from last update
int b = 1; // last discrepancy
for (int n = 0; n < (int)s.size(); n++) {
int d = 0;
for (int i = 0; i <= L; i++) {
if (n - i < 0) break;
d = (d + 1ll * C[i] * s[n - i]) % P;
}
if (d == 0) {
m++;
continue;
}
poly T = C;
// coef = d / b
int coef = 1LL * d * inv(b) % P;
// C = C - coef * x^m * B
if ((int)C.size() < (int)B.size() + m) C.resize(B.size() + m, 0);
for (int i = 0; i < (int)B.size(); i++) {
C[i + m] = C[i + m] - 1ll * coef * B[i] % P;
if(C[i + m] < 0)C[i + m] += P;
}
if (2 * L <= n) {
L = n + 1 - L;
B = T;
b = d;
m = 1;
} else {
m++;
}
}
return -C;
}
namespace compositon{
using biPoly = vector<poly>; // sum_{j>=0} A[j](x) * y^j
// (A*B) mod x^nx, y^my
// packing: x^i y^j -> t^{i + j*block}
biPoly biMul(const biPoly& A, const biPoly& B, int nx, int my) {
int Ay = min<int>(A.size(), my);
int By = min<int>(B.size(), my);
if (Ay == 0 || By == 0) return {};
int Cy = min<int>(Ay + By - 1, my);
int block = 2 * nx - 1;
poly PA(Ay * block), PB(By * block);
for (int j = 0; j < Ay; j++) {
int lim = min<int>(nx, A[j].size());
for (int i = 0; i < lim; i++) PA[j * block + i] = A[j][i];
}
for (int j = 0; j < By; j++) {
int lim = min<int>(nx, B[j].size());
for (int i = 0; i < lim; i++) PB[j * block + i] = B[j][i];
}
poly PC = PA * PB;
biPoly C(Cy, poly(nx));
for (int j = 0; j < Cy; j++) {
int base = j * block;
for (int i = 0; i < nx; i++) {
int idx = base + i;
if (idx < (int)PC.size()) C[j][i] = PC[idx];
}
}
return C;
}
// Q(-x,y)
biPoly neg_x(const biPoly& Q, int nx) {
biPoly R = Q;
for (auto& fx : R) {
if ((int)fx.size() < nx) fx.resize(nx);
for (int i = 1; i < nx; i += 2){
fx[i] = -fx[i];
if(fx[i] < 0)fx[i] += P;
}
}
return R;
}
// V(x^2,y) = A(x,y)
// 输入 A mod x^nx,输出 V mod x^{ceil(nx/2)}
biPoly even_x(const biPoly& A, int nx) {
int nx2 = (nx + 1) / 2;
biPoly V(A.size(), poly(nx2));
for (int j = 0; j < (int)A.size(); j++) {
int lim = min<int>(nx, A[j].size());
for (int i = 0; i < nx2; i++) {
int k = 2 * i;
if (k < lim) V[j][i] = A[j][k];
}
}
return V;
}
// W(x^2,y) mod x^nx
biPoly subst_x2(const biPoly& W, int nx) {
biPoly R(W.size(), poly(nx));
for (int j = 0; j < (int)W.size(); j++) {
for (int i = 0; i < (int)W[j].size(); i++) {
int k = 2 * i;
if (k < nx) R[j][k] = W[j][i];
}
}
return R;
}
// 取 y 的 [l, r) 段并左移:返回 size=r-l
biPoly slice_y(const biPoly& A, int l, int r, int nx) {
int len = max(0, r - l);
biPoly R(len, poly(nx));
for (int i = 0; i < len; i++) {
int j = l + i;
if (0 <= j && j < (int)A.size()) {
R[i] = A[j].trunc(nx);
}
}
return R;
}
// 忠实版 Comp:返回 F_{d,m}( P(y) / Q(x,y) ) mod x^nx
// P 是 y 多项式(长度 m);Q 是 biPoly(y>=0)
// 返回 biPoly,size = m-d,且每项是 x 多项式(长度 nx)
biPoly Comp(const poly& P, const biPoly& Q,int nx, int d, int m) {
// base: x 只剩常数项
if (nx == 1) {
// Q0(y) = Q(0,y)
poly Q0(m);
int limy = min<int>(m, Q.size());
for (int j = 0; j < limy; j++) {
if (!Q[j].empty()) Q0[j] = Q[j][0];
}
// C(y) = P(y) / Q0(y) mod y^m
poly C = (P * Q0.inv(m)).trunc(m);
// 输出 y 的 [d,m)
biPoly res(m - d, poly(1));
for (int i = d; i < m; i++) res[i - d][0] = C[i];
return res;
}
int degyQ = min(m - 1, (int)Q.size() - 1);
int e = max(0, d - degyQ);
biPoly Qneg = neg_x(Q, nx);
// A = Q * Q(-x) (mod x^nx, y^m)
biPoly A = biMul(Q, Qneg, nx, m);
// V(x,y) = A_even(x,y) with x := x^2 collapsed, so xlen halves
biPoly V = even_x(A, nx);
int nx2 = (nx + 1) / 2;
// W = Comp(nx2, e, m, P, V) (y窗口从 e 开始)
biPoly W = Comp(P, V, nx2, e, m);
// lift: W(x^2,y)
biPoly W2 = subst_x2(W, nx);
// B = W(x^2,y) * Q(-x,y) 只需要 y < (m-e)
biPoly B = biMul(W2, Qneg, nx, m - e);
// 返回 y 的 [d-e, m-e)
return slice_y(B, d - e, m - e, nx);
}
poly comp(poly f, poly g, int n) {
f = f.trunc(n);
g = g.trunc(n);
if ((int)g.size() < n) g.resize(n);
int m = min<int>(n, f.size());
// P(y) = y^{m-1} f(1/y) <=> P[i] = f[m-1-i]
poly P(m);
for (int i = 0; i < m; i++) P[i] = f[m - 1 - i];
// Q(x,y) = 1 - y g(x)
biPoly Q(2, poly(n));
Q[0][0] = 1;
Q[1] = (-g).trunc(n);
if ((int)Q[1].size() < n) Q[1].resize(n);
// 取 y^{m-1}:即 d=m-1, 输出 size=1
biPoly R = Comp(P, Q, n, m - 1, m);
return R[0].trunc(n);
}
biPoly biMul_fullX(const biPoly& A, const biPoly& B, int nx_in, int my) {
int Ay = std::min<int>((int)A.size(), my);
int By = std::min<int>((int)B.size(), my);
if (Ay == 0 || By == 0) return {};
int Cy = std::min<int>(Ay + By - 1, my);
int nx_out = 2 * nx_in - 1;
// block must be >= nx_out to avoid x-carry crossing y-blocks
int block = nx_out;
poly PA(Ay * block), PB(By * block);
for (int j = 0; j < Ay; j++) {
int lim = std::min<int>(nx_in, (int)A[j].size());
for (int i = 0; i < lim; i++) PA[j * block + i] = A[j][i];
}
for (int j = 0; j < By; j++) {
int lim = std::min<int>(nx_in, (int)B[j].size());
for (int i = 0; i < lim; i++) PB[j * block + i] = B[j][i];
}
poly PC = PA * PB;
biPoly C(Cy, poly(nx_out));
for (int j = 0; j < Cy; j++) {
int base = j * block;
for (int i = 0; i < nx_out; i++) {
int idx = base + i;
if (idx < (int)PC.size()) C[j][i] = PC[idx];
}
}
return C;
}
// pick x-parity and downsample: keep coeffs x^{2t+parity} -> new[t]
biPoly pick_parity_x(const biPoly& A, int parity, int nx_new) {
biPoly R(A.size(), poly(nx_new));
for (int j = 0; j < (int)A.size(); j++) {
int lim = (int)A[j].size();
for (int t = 0; t < nx_new; t++) {
int idx = 2 * t + parity;
if (idx < lim) R[j][t] = A[j][idx];
}
}
return R;
}
// ans[k] = [x^n] f(x)^k * g(x), k=0..n
// require f.size()==g.size()==n+1 and f[0]==0
poly powerProjection(poly f, poly g) {
int N = (int)f.size();
int n = N - 1;
// 当前 xlen = n+1, 当前 ylen = my
int nx = n + 1;
int my = std::min(N, 2); // 初始 Q = 1 - y f, 只需要 y^0..y^1
biPoly P, Q;
P.assign(1, g.trunc(nx)); // P(y) = g(x)
Q.assign(2, poly(nx)); // Q(y) = 1 - y f(x)
Q[0][0] = 1;
Q[1] = (-f).trunc(nx);
// 主循环:x-Bostan–Mori,目标提取 [x^n]
while (n > 0) {
// ylen 更新:乘法会让 ylen 至多变成 2*my-1,但我们只关心到 N 项
int my2 = std::min(N, 2 * my - 1);
// R = Q(-x,y)
biPoly R = neg_x(Q, nx);
// S = P * R , T = Q * R (x full conv, y truncated)
biPoly S = biMul_fullX(P, R, nx, my2);
biPoly T = biMul_fullX(Q, R, nx, my2);
int parity = (n & 1);
int n2 = n >> 1;
int nx2 = n2 + 1;
// P <- pick parity row from S; Q <- even row from T
P = pick_parity_x(S, parity, nx2);
Q = pick_parity_x(T, 0, nx2);
// 截 ylen 到 my2(pick_parity_x 保留了全部 y 行)
if ((int)P.size() > my2) P.resize(my2);
if ((int)Q.size() > my2) Q.resize(my2);
// shrink n, nx, my
n = n2;
nx = nx2;
my = my2;
}
// n == 0 => x 只剩常数项:结果是 y-series = P0(y)/Q0(y)
// 取各 y^j 的 x^0 系数拼成 y 多项式
poly Py(my), Qy(my);
for (int j = 0; j < my; j++) {
if (j < (int)P.size() && !P[j].empty()) Py[j] = P[j][0];
if (j < (int)Q.size() && !Q[j].empty()) Qy[j] = Q[j][0];
}
poly invQy = Qy.inv(my);
poly ans = (Py * invQy).trunc(N); // 需要 0..N-1 共 N 项(k=0..n)
return ans;
}
// g = f^{<-1>} mod x^m, require f[0]=0 and f[1]!=0
poly compInv(poly f, int m) {
if (m <= 0) return poly();
if (m == 1) return poly{0};
f = f.trunc(m);
// assert(f.size() >= 2 && f[0] == 0 && f[1] != 0);
int c = f[1];
// powerProjection 需要 size = (m+1): n = m
poly fext = f;
fext.resize(m + 1); // f[m]=0 不影响 mod x^m 的 inverse
poly one(m + 1);
one[0] = 1;
// hk[k] = [x^m] f(x)^k
poly hk = powerProjection(fext, one); // length m+1
// A(x) = (x/g)^m mod x^m (length m)
poly A(m);
for (int k = 1; k <= m; k++) {
int deg = m - k;
// coeff = m/k * hk[k]
int coef = (long long)m * inv(k) % P * hk[k] % P;
A[deg] = coef;
}
// normalize by c^m so that B[0]=1
int cpm = power(c, m);
poly B = A / cpm;
// (optional) assert(B[0] == 1);
// H = x/g = c * exp( log(B)/m )
poly L = (B.log(m) / m); // /m uses scalar inverse via your operator/(int)
poly H = L.exp(m) * c;
// g = x * inv(H)
poly invH = H.inv(m);
poly ginv = invH.shift(1).trunc(m);
return ginv;
}
}
void solve()
{
}
int main()
{
std::ios::sync_with_stdio(0);
std::cin.tie(0);
int tt = 1;
//cin >> tt;
while(tt--){
solve();
}
return 0;
}





