use std::io::Read; fn get_word() -> String { let stdin = std::io::stdin(); let mut stdin=stdin.lock(); let mut u8b: [u8; 1] = [0]; loop { let mut buf: Vec<u8> = Vec::with_capacity(16); loop { let res = stdin.read(&mut u8b); if res.unwrap_or(0) == 0 || u8b[0] <= b' ' { break; } else { buf.push(u8b[0]); } } if buf.len() >= 1 { let ret = String::from_utf8(buf).unwrap(); return ret; } } } fn get<T: std::str::FromStr>() -> T { get_word().parse().ok().unwrap() } /// Verified by https://atcoder.jp/contests/abc198/submissions/21774342 mod mod_int { use std::ops::*; pub trait Mod: Copy { fn m() -> i64; } #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)] pub struct ModInt<M> { pub x: i64, phantom: ::std::marker::PhantomData<M> } impl<M: Mod> ModInt<M> { // x >= 0 pub fn new(x: i64) -> Self { ModInt::new_internal(x % M::m()) } fn new_internal(x: i64) -> Self { ModInt { x: x, phantom: ::std::marker::PhantomData } } pub fn pow(self, mut e: i64) -> Self { debug_assert!(e >= 0); let mut sum = ModInt::new_internal(1); let mut cur = self; while e > 0 { if e % 2 != 0 { sum *= cur; } cur *= cur; e /= 2; } sum } #[allow(dead_code)] pub fn inv(self) -> Self { self.pow(M::m() - 2) } } impl<M: Mod> Default for ModInt<M> { fn default() -> Self { Self::new_internal(0) } } impl<M: Mod, T: Into<ModInt<M>>> Add<T> for ModInt<M> { type Output = Self; fn add(self, other: T) -> Self { let other = other.into(); let mut sum = self.x + other.x; if sum >= M::m() { sum -= M::m(); } ModInt::new_internal(sum) } } impl<M: Mod, T: Into<ModInt<M>>> Sub<T> for ModInt<M> { type Output = Self; fn sub(self, other: T) -> Self { let other = other.into(); let mut sum = self.x - other.x; if sum < 0 { sum += M::m(); } ModInt::new_internal(sum) } } impl<M: Mod, T: Into<ModInt<M>>> Mul<T> for ModInt<M> { type Output = Self; fn mul(self, other: T) -> Self { ModInt::new(self.x * other.into().x % M::m()) } } impl<M: Mod, T: Into<ModInt<M>>> AddAssign<T> for ModInt<M> { fn add_assign(&mut self, other: T) { *self = *self + other; } } impl<M: Mod, T: Into<ModInt<M>>> SubAssign<T> for ModInt<M> { fn sub_assign(&mut self, other: T) { *self = *self - other; } } impl<M: Mod, T: Into<ModInt<M>>> MulAssign<T> for ModInt<M> { fn mul_assign(&mut self, other: T) { *self = *self * other; } } impl<M: Mod> Neg for ModInt<M> { type Output = Self; fn neg(self) -> Self { ModInt::new(0) - self } } impl<M> ::std::fmt::Display for ModInt<M> { fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result { self.x.fmt(f) } } impl<M: Mod> ::std::fmt::Debug for ModInt<M> { fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result { let (mut a, mut b, _) = red(self.x, M::m()); if b < 0 { a = -a; b = -b; } write!(f, "{}/{}", a, b) } } impl<M: Mod> From<i64> for ModInt<M> { fn from(x: i64) -> Self { Self::new(x) } } // Finds the simplest fraction x/y congruent to r mod p. // The return value (x, y, z) satisfies x = y * r + z * p. fn red(r: i64, p: i64) -> (i64, i64, i64) { if r.abs() <= 10000 { return (r, 1, 0); } let mut nxt_r = p % r; let mut q = p / r; if 2 * nxt_r >= r { nxt_r -= r; q += 1; } if 2 * nxt_r <= -r { nxt_r += r; q -= 1; } let (x, z, y) = red(nxt_r, r); (x, y - q * z, z) } } // mod mod_int macro_rules! define_mod { ($struct_name: ident, $modulo: expr) => { #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)] pub struct $struct_name {} impl mod_int::Mod for $struct_name { fn m() -> i64 { $modulo } } } } const MOD: i64 = 998_244_353; define_mod!(P, MOD); type MInt = mod_int::ModInt<P>; // FFT (in-place, verified as NTT only) // R: Ring + Copy // Verified by: https://judge.yosupo.jp/submission/53831 // Adopts the technique used in https://judge.yosupo.jp/submission/3153. mod fft { use std::ops::*; // n should be a power of 2. zeta is a primitive n-th root of unity. // one is unity // Note that the result is bit-reversed. pub fn fft<R>(f: &mut [R], zeta: R, one: R) where R: Copy + Add<Output = R> + Sub<Output = R> + Mul<Output = R> { let n = f.len(); assert!(n.is_power_of_two()); let mut m = n; let mut base = zeta; unsafe { while m > 2 { m >>= 1; let mut r = 0; while r < n { let mut w = one; for s in r..r + m { let &u = f.get_unchecked(s); let d = *f.get_unchecked(s + m); *f.get_unchecked_mut(s) = u + d; *f.get_unchecked_mut(s + m) = w * (u - d); w = w * base; } r += 2 * m; } base = base * base; } if m > 1 { // m = 1 let mut r = 0; while r < n { let &u = f.get_unchecked(r); let d = *f.get_unchecked(r + 1); *f.get_unchecked_mut(r) = u + d; *f.get_unchecked_mut(r + 1) = u - d; r += 2; } } } } pub fn inv_fft<R>(f: &mut [R], zeta_inv: R, one: R) where R: Copy + Add<Output = R> + Sub<Output = R> + Mul<Output = R> { let n = f.len(); assert!(n.is_power_of_two()); let zeta = zeta_inv; // inverse FFT let mut zetapow = Vec::with_capacity(20); { let mut m = 1; let mut cur = zeta; while m < n { zetapow.push(cur); cur = cur * cur; m *= 2; } } let mut m = 1; unsafe { if m < n { zetapow.pop(); let mut r = 0; while r < n { let &u = f.get_unchecked(r); let d = *f.get_unchecked(r + 1); *f.get_unchecked_mut(r) = u + d; *f.get_unchecked_mut(r + 1) = u - d; r += 2; } m = 2; } while m < n { let base = zetapow.pop().unwrap(); let mut r = 0; while r < n { let mut w = one; for s in r..r + m { let &u = f.get_unchecked(s); let d = *f.get_unchecked(s + m) * w; *f.get_unchecked_mut(s) = u + d; *f.get_unchecked_mut(s + m) = u - d; w = w * base; } r += 2 * m; } m *= 2; } } } } // Depends on: fft.rs, MInt.rs // Verified by: ABC269-Ex (https://atcoder.jp/contests/abc269/submissions/39116328) pub struct FPSOps<M: mod_int::Mod = P> { gen: mod_int::ModInt<M>, } impl<M: mod_int::Mod> FPSOps<M> { pub fn new(gen: mod_int::ModInt<M>) -> Self { FPSOps { gen: gen } } } impl<M: mod_int::Mod> FPSOps<M> { pub fn add(&self, mut a: Vec<mod_int::ModInt<M>>, mut b: Vec<mod_int::ModInt<M>>) -> Vec<mod_int::ModInt<M>> { if a.len() < b.len() { std::mem::swap(&mut a, &mut b); } for i in 0..b.len() { a[i] += b[i]; } a } pub fn mul(&self, a: Vec<mod_int::ModInt<M>>, b: Vec<mod_int::ModInt<M>>) -> Vec<mod_int::ModInt<M>> { type MInt<M> = mod_int::ModInt<M>; let n = a.len() - 1; let m = b.len() - 1; let mut p = 1; while p <= n + m { p *= 2; } let mut f = vec![MInt::new(0); p]; let mut g = vec![MInt::new(0); p]; for i in 0..n + 1 { f[i] = a[i]; } for i in 0..m + 1 { g[i] = b[i]; } let fac = MInt::new(p as i64).inv(); let zeta = self.gen.pow((M::m() - 1) / p as i64); fft::fft(&mut f, zeta, 1.into()); fft::fft(&mut g, zeta, 1.into()); for i in 0..p { f[i] *= g[i] * fac; } fft::inv_fft(&mut f, zeta.inv(), 1.into()); f.truncate(n + m + 1); f } } // Computes f^{-1} mod x^{f.len()}. // Reference: https://codeforces.com/blog/entry/56422 // Complexity: O(n log n) // Verified by: https://judge.yosupo.jp/submission/3219 // Depends on: MInt.rs, fft.rs fn fps_inv<P: mod_int::Mod + PartialEq>( f: &[mod_int::ModInt<P>], gen: mod_int::ModInt<P> ) -> Vec<mod_int::ModInt<P>> { let n = f.len(); assert!(n.is_power_of_two()); assert_eq!(f[0], 1.into()); let mut sz = 1; let mut r = vec![mod_int::ModInt::new(0); n]; let mut tmp_f = vec![mod_int::ModInt::new(0); n]; let mut tmp_r = vec![mod_int::ModInt::new(0); n]; r[0] = 1.into(); // Adopts the technique used in https://judge.yosupo.jp/submission/3153 while sz < n { let zeta = gen.pow((P::m() - 1) / sz as i64 / 2); tmp_f[..2 * sz].copy_from_slice(&f[..2 * sz]); tmp_r[..2 * sz].copy_from_slice(&r[..2 * sz]); fft::fft(&mut tmp_r[..2 * sz], zeta, 1.into()); fft::fft(&mut tmp_f[..2 * sz], zeta, 1.into()); let fac = mod_int::ModInt::new(2 * sz as i64).inv().pow(2); for i in 0..2 * sz { tmp_f[i] *= tmp_r[i]; } fft::inv_fft(&mut tmp_f[..2 * sz], zeta.inv(), 1.into()); for v in &mut tmp_f[..sz] { *v = 0.into(); } fft::fft(&mut tmp_f[..2 * sz], zeta, 1.into()); for i in 0..2 * sz { tmp_f[i] = -tmp_f[i] * tmp_r[i] * fac; } fft::inv_fft(&mut tmp_f[..2 * sz], zeta.inv(), 1.into()); r[sz..2 * sz].copy_from_slice(&tmp_f[sz..2 * sz]); sz *= 2; } r } type M = MInt; // Copied and modified from https://judge.yosupo.jp/submission/133199. // Originally by sansen. fn middle_product(c: &[M], a: &[M]) -> Vec<M> { assert!(c.len() >= a.len()); if a.len() <= (1 << 5) { return c .windows(a.len()) .map(|c| { c.iter() .zip(a.iter()) .fold(MInt::new(0), |s, a| s + *a.0 * *a.1) }) .collect(); } let size = c.len().next_power_of_two(); let mut x = Vec::from(c); x.resize(size, MInt::new(0)); let mut y = Vec::from(a); y.reverse(); y.resize(size, MInt::new(0)); let zeta = MInt::new(3).pow((MOD - 1) / size as i64); fft::fft(&mut x, zeta, 1.into()); fft::fft(&mut y, zeta, 1.into()); let factor = MInt::new(size as i64).inv(); for i in 0..size { x[i] *= y[i] * factor; } fft::inv_fft(&mut x, zeta.inv(), 1.into()); (a.len()..=c.len()).map(|z| x[z - 1]).collect() } fn multipoint_evaluation(ops: &FPSOps, c: &[MInt], p: &[MInt]) -> Vec<M> { if p.is_empty() { return vec![]; } let n = c.len(); let m = p.len(); let mut prod = vec![vec![]; 2 * m]; for (prod, p) in prod[m..].iter_mut().zip(p.iter()) { *prod = vec![MInt::new(1), -*p]; } for i in (1..m).rev() { prod[i] = ops.mul(prod[2 * i].clone(), prod[2 * i + 1].clone()); } let mut prod1 = prod[1].clone(); let mut sz = 1; while sz < n { sz *= 2; } prod1.resize(sz, 0.into()); let mut inv = fps_inv(&prod1, 3.into()); inv.truncate(n); let mut c = c.to_vec(); c.resize(n + m - 1, MInt::new(0)); let mut dp = vec![vec![]; 2 * m]; dp[1] = middle_product(&c, &inv); for i in 1..m { dp[2 * i] = middle_product(&dp[i], &prod[2 * i + 1]); dp[2 * i + 1] = middle_product(&dp[i], &prod[2 * i]); } dp[m..].iter().map(|dp| dp[0]).collect() } // End of copy-pasted part. fn fps_mul_all(ops: &FPSOps, f: &[Vec<MInt>]) -> Vec<MInt> { let m = f.len(); let mut seg = vec![vec![]; 2 * m]; for i in 0..m { seg[i + m] = f[i].to_vec(); } for i in (1..m).rev() { seg[i] = ops.mul( std::mem::replace(&mut seg[2 * i], vec![]), std::mem::replace(&mut seg[2 * i + 1], vec![]), ); } std::mem::replace(&mut seg[1], vec![]) } fn fps_common_denom(ops: &FPSOps, frac: &[(Vec<MInt>, Vec<MInt>)]) -> (Vec<MInt>, Vec<MInt>) { let m = frac.len(); let mut seg = vec![(vec![], vec![]); 2 * m]; for i in 0..m { seg[i + m] = frac[i].clone(); } for i in (1..m).rev() { let den = ops.mul(seg[2 * i].1.clone(), seg[2 * i + 1].1.clone()); let mut num = ops.mul( std::mem::replace(&mut seg[2 * i].1, vec![]), std::mem::replace(&mut seg[2 * i + 1].0, vec![]), ); let tmp = ops.mul( std::mem::replace(&mut seg[2 * i].0, vec![]), std::mem::replace(&mut seg[2 * i + 1].1, vec![]), ); num = ops.add(num, tmp); seg[i] = (num, den); } std::mem::replace(&mut seg[1], (vec![], vec![])) } // https://37zigen.com/lagrange-interpolation/ fn lagrange_interpolate(ops: &FPSOps, xy: &[(MInt, MInt)]) -> Vec<MInt> { let n = xy.len(); let mut xs = vec![MInt::new(0); n]; let mut ps = vec![vec![]; n]; for i in 0..n { xs[i] = xy[i].0; ps[i] = vec![-xy[i].0, 1.into()]; } let g = fps_mul_all(ops, &ps); let mut gdash = vec![MInt::new(0); n]; for i in 0..n { gdash[i] = g[i + 1] * (i + 1) as i64; } let vals = multipoint_evaluation(ops, &gdash, &xs); let mut fracs = vec![(vec![MInt::new(1)], vec![]); n]; for i in 0..n { fracs[i].0[0] = vals[i].inv() * xy[i].1; fracs[i].1 = vec![-xy[i].0, 1.into()]; } let (num, _) = fps_common_denom(ops, &fracs); num } // Generated by 2747-helper.rs const STEP: usize = 1000000; const LEN: usize = 1000; const FACT_TABLE: [i64; 1000] = [ 1, 373341033, 45596018, 834980587, 623627864, 428937595, 442819817, 499710224, 833655840, 83857087, 295201906, 788488293, 671639287, 849315549, 597398273, 813259672, 732727656, 244038325, 122642896, 310517972, 160030060, 483239722, 683879839, 712910418, 384710263, 433880730, 844360005, 513089677, 101492974, 959253371, 957629942, 678615452, 34035221, 56734233, 524027922, 31729117, 102311167, 330331487, 8332991, 832392662, 545208507, 594075875, 318497156, 859275605, 300738984, 767818091, 864118508, 878131539, 316588744, 812496962, 213689172, 584871249, 980836133, 54096741, 417876813, 363266670, 335481797, 730839588, 393495668, 435793297, 760025067, 811438469, 720976283, 650770098, 586537547, 117371703, 566486504, 749562308, 708205284, 932912293, 939830261, 983699513, 206579820, 301188781, 593164676, 770845925, 247687458, 41047791, 266419267, 937835947, 506268060, 6177705, 936268003, 166873118, 443834893, 328979964, 470135404, 954410105, 117565665, 832761782, 39806322, 478922755, 394880724, 821825588, 468705875, 512554988, 232240472, 876497899, 356048018, 895187265, 808258749, 575505950, 68190615, 939065335, 552199946, 694814243, 385460530, 529769387, 640377761, 916128300, 440133909, 362216114, 826373774, 502324157, 457648395, 385510728, 904737188, 78988746, 454565719, 623828097, 686156489, 713476044, 63602402, 570334625, 681055904, 222059821, 477211096, 343363294, 833792655, 461853093, 741797144, 74731896, 930484262, 268372735, 941222802, 677432735, 474842829, 700451655, 400176109, 697644778, 390377694, 790010794, 360642718, 505712943, 946647976, 339045014, 715797300, 251680896, 70091750, 40517433, 12629586, 850635539, 110877109, 571935891, 695965747, 634938288, 69072133, 155093216, 749696762, 963086402, 544711799, 724471925, 334646013, 574791029, 722417626, 377929821, 743946412, 988034679, 405207112, 18063742, 104121967, 638607426, 607304611, 751377777, 35834555, 313632531, 18058363, 656121134, 40763559, 562910912, 495867250, 48767038, 210864657, 659137294, 715390025, 865854329, 324322857, 388911184, 286059202, 636456178, 421290700, 832276048, 726437551, 526417714, 252522639, 386147469, 674313019, 274769381, 226519400, 272047186, 117153405, 712896591, 486826649, 119444874, 338909703, 18536028, 41814114, 245606459, 140617938, 250512392, 57084755, 157807456, 261113192, 40258068, 194807105, 325341339, 884328111, 896332013, 880836012, 737358206, 202713771, 785454372, 399586250, 485457499, 640827004, 546969497, 749602473, 159788463, 159111724, 218592929, 675932866, 314795475, 811539323, 246883213, 696818315, 759880589, 4302336, 353070689, 477909706, 559289160, 79781699, 878094972, 840903973, 367416824, 973366814, 848259019, 462421750, 667227759, 897917455, 81800722, 956276337, 942686845, 420541799, 417005912, 272641764, 941778993, 217214373, 192220616, 267901132, 50530621, 652678397, 354880856, 164289049, 781023184, 105376215, 315094878, 607856504, 733905911, 457743498, 992735713, 35212756, 231822660, 276036750, 734558079, 424180850, 433186147, 308380947, 18333316, 12935086, 351491725, 655645460, 535812389, 521902115, 67016984, 48682076, 64748124, 489360447, 361275315, 786336279, 805161272, 468129309, 645091350, 887284732, 913004502, 358814684, 281295633, 328970139, 395955130, 164840186, 820902807, 761699708, 246274415, 592331769, 913846362, 866682684, 600130702, 903837674, 529462989, 90612675, 526540127, 533047427, 110008879, 674279751, 801920753, 645226926, 676886948, 752481486, 474034007, 457790341, 166813684, 287671032, 188118664, 244731384, 404032157, 269766986, 423996017, 182948540, 356801634, 737863144, 652014069, 206068022, 504569410, 919894484, 593398649, 963768176, 882517476, 702523597, 949028249, 128957299, 171997372, 50865043, 20937461, 690959202, 581356488, 369182214, 993580422, 193500140, 540665426, 365786018, 743731625, 144980423, 979536721, 773259009, 617053935, 247670131, 843705280, 30419459, 985463402, 261585206, 237885042, 111276893, 488166208, 137660292, 720784236, 244467770, 26368504, 792857103, 666885724, 670313309, 905683034, 259415897, 512017253, 826265493, 111960112, 633652060, 918048438, 516432938, 386972415, 996212724, 610073831, 444094191, 72480267, 665038087, 11584804, 301029012, 723617861, 113763819, 778259899, 937766095, 535448641, 593907889, 783573565, 673298635, 599533244, 655712590, 173350007, 868198597, 169013813, 585161712, 697502214, 573994984, 285943986, 675831407, 3134056, 965907646, 401920943, 665949756, 236277883, 612745912, 813282113, 892454686, 901222267, 624900982, 927122298, 686321335, 84924870, 927606072, 506664166, 353631992, 165913238, 566073550, 816674343, 864877926, 171259407, 908752311, 874007723, 803597299, 613676466, 880336545, 282280109, 128761001, 58852065, 474075900, 434816091, 364856903, 149123648, 388854780, 314693916, 423183826, 419733481, 888483202, 238933227, 336564048, 757103493, 100189123, 855479832, 51370348, 403061033, 496971759, 831753030, 251718753, 272779384, 683379259, 488844621, 881783783, 659478190, 445719559, 740782647, 546525906, 985524427, 548033568, 333772553, 331916427, 752533273, 730387628, 93829695, 655989476, 930661318, 334885743, 466041862, 428105027, 888238707, 232218076, 769865249, 730641039, 616996159, 231721356, 326973501, 426068899, 722403656, 742756734, 663270261, 364187931, 350431704, 671823672, 633125919, 226166717, 386814657, 237594135, 451479365, 546182474, 119366536, 465211069, 605313606, 728508871, 249619035, 663053607, 900453742, 48293872, 229958401, 62402409, 69570431, 71921532, 960467929, 537087913, 514588945, 513856225, 415497414, 286592050, 645469437, 102052166, 163298189, 873938719, 617583886, 986843080, 962390239, 580971332, 665147020, 88900164, 89866970, 826426395, 616059995, 443012312, 659160562, 229855967, 687413213, 59809521, 398599610, 325666688, 154765991, 159186619, 210830877, 386454418, 84493735, 974220646, 820097297, 2191828, 481459931, 729073424, 551556379, 926316039, 151357011, 808637654, 218058015, 786112034, 850407126, 84202800, 94214098, 30019651, 121701603, 176055335, 865461951, 553631971, 286620803, 984061713, 888573766, 302767023, 977070668, 110954576, 83922475, 51568171, 60949367, 19533020, 510592752, 615419476, 341370469, 912573425, 286207526, 206707897, 384156962, 414163604, 193301813, 749570167, 366933789, 11470970, 600191572, 391667731, 328736286, 30645366, 215162519, 604947226, 236199953, 718439098, 411423177, 803407599, 632441623, 766760224, 263006576, 757681534, 61082578, 681666415, 947466395, 12206799, 659767098, 933746852, 978860867, 59215985, 161179205, 439197472, 259779111, 511621808, 145770512, 882749888, 943124465, 872053396, 631078482, 166861622, 743415395, 772287179, 602427948, 924112080, 385643091, 794973480, 883782693, 869723371, 805963889, 313106351, 262132854, 400034567, 488248149, 265769800, 791715397, 408753255, 468381897, 415812467, 172922144, 64404368, 281500398, 512318142, 288791777, 955559118, 242484726, 536413695, 205340854, 707803527, 576699812, 218525078, 875554190, 46283078, 833841915, 763148293, 807722138, 788080170, 556901372, 150896699, 253151120, 97856807, 918256774, 771557187, 582547026, 472709375, 911615063, 743371401, 641382840, 446540967, 184639537, 157247760, 775930891, 939702814, 499082462, 19536133, 548753627, 593243221, 563850263, 185475971, 687419227, 396799323, 657976136, 864535682, 433009242, 860830935, 33107339, 517661450, 467651311, 812398757, 202133852, 431839017, 709549400, 99643620, 773282878, 290471030, 61134552, 129206504, 929147251, 837008968, 422332597, 353775281, 469563025, 62265336, 835064501, 851685235, 21197005, 264793769, 326416680, 118842991, 84257200, 763248924, 687559609, 150907932, 401832452, 242726978, 766752066, 959173604, 390269102, 992293822, 744816299, 476631694, 177284763, 702429415, 374065901, 169855231, 629007616, 719169602, 564737074, 475119050, 714502830, 40993711, 820235888, 749063595, 239329111, 612759169, 18591377, 419142436, 442202439, 941600951, 158013406, 637073231, 471564060, 447222237, 701248503, 599797734, 577221870, 69656699, 51052704, 6544303, 10958310, 554955500, 943192237, 192526269, 897983911, 961628039, 240232720, 627280533, 710239542, 70255649, 261743865, 228474833, 776408079, 304180483, 63607040, 953297493, 758058902, 395529997, 156010331, 825833840, 539880795, 234683685, 52626619, 751843490, 116909119, 62806842, 574857555, 353417551, 40061330, 822203768, 681051568, 490913702, 9322961, 766631257, 124794668, 37844313, 163524507, 729108319, 490867505, 47035168, 682765157, 53842115, 817965276, 757179922, 339238384, 909741023, 150530547, 158444563, 140949492, 993302799, 551621442, 137578883, 475122706, 443869843, 605400098, 689361523, 769596520, 801661499, 474900284, 586624857, 349960501, 134084537, 650564083, 877097974, 379857427, 887890124, 159436401, 133274277, 986182139, 729720334, 568925901, 459461496, 499309445, 493171177, 460958750, 380694152, 168836226, 840160881, 141116880, 225064950, 109618190, 842341383, 85305729, 759273275, 97369807, 669317759, 766247510, 829017039, 550323884, 261274540, 918239352, 29606025, 870793828, 293683814, 378510746, 367270918, 481292028, 813097823, 798448487, 230791733, 899305835, 504040630, 162510533, 479367951, 275282274, 806951470, 462774647, 56473153, 184659008, 905122161, 664034750, 109726629, 59372704, 325795100, 486860143, 843736533, 924723613, 880348000, 801252478, 616515290, 776142608, 284803450, 583439582, 274826676, 6018349, 377403437, 244041569, 527081707, 544763288, 708818585, 354033051, 904309832, 589922898, 673933870, 682858433, 945260111, 899893421, 515264973, 911685911, 9527148, 239480646, 524126897, 48259065, 578214879, 118677219, 786127243, 869205770, 923276513, 937928886, 802186160, 12198440, 638784295, 34200904, 758925811, 185027790, 80918046, 120604699, 610456697, 573601211, 208296321, 49743354, 653691911, 490750754, 674335312, 887877110, 875880304, 308360096, 414636410, 886100267, 8525751, 636257427, 558338775, 500159951, 696213291, 97268896, 364983542, 937928436, 641582714, 586211304, 345265657, 994704486, 443549763, 207259440, 302122082, 166055224, 623250998, 239642551, 476337075, 283167364, 211328914, 68064804, 950202136, 187552679, 18938709, 646784245, 598764068, 538505481, 610424991, 864445053, 390248689, 278395191, 686098470, 935957187, 868529577, 329970687, 804930040, 84992079, 474569269, 810762228, 573258936, 756464212, 155080225, 286966169, 283614605, 19283401, 24257676, 871831819, 612689791, 846988741, 617120754, 971716517, 979541482, 297910784, 991087897, 783825907, 214821357, 689498189, 405026419, 946731704, 609346370, 707669156, 457703127, 957341187, 980735523, 649367684, 791011898, 82098966, 234729712, 105002711, 130614285, 291032164, 193188049, 363211260, 58108651, 100756444, 954947696, 346032213, 863300806, 36876722, 622610957, 289232396, 667938985, 734886266, 395881057, 417188702, 183092975, 887586469, 83334648, 797819763, 100176902, 781587414, 841864935, 371674670, 18247584, 0, ]; // https://yukicoder.me/problems/no/2747 (3.5) // solved with hints // \sum_{1 <= i <= N} (N-i)i^K が計算できれば良い。これはベルヌーイ数の先頭 K 項が O(K log K)-time 程度で計算できれば計算できる。 // -> 解説を見た。ラグランジュ補間の方が簡単。最終的な多項式は K+2 次なので、0 <= i <= K+2 の K+3 点で補間する。 // 最後に (N-2)! * (N-1) * 2 を掛けること。 // - (N-2)!: 残りの点の埋め方 // - (N-1): どの隙間を見るか // - 2: 左の方が大きいか // Tags: lagrange-polynomial-interpolation, lagrange-interpolation fn main() { let n: i64 = get(); let k: i64 = get(); let ops = FPSOps { gen: 3.into(), }; let mut xy = vec![]; let mut sum = MInt::new(0); for i in 0..k + 3 { sum += MInt::new(i).pow(k) * (n - i); xy.push((MInt::new(i), sum)); } let p = lagrange_interpolate(&ops, &xy); let mut ans = MInt::new(0); let mut cur = MInt::new(1); for elem in p { ans += elem * cur; cur *= n; } ans *= 2; let tbl_idx = ((n - 1) as usize / STEP).min(LEN - 1); let mut fac = MInt::new(FACT_TABLE[tbl_idx]); for i in tbl_idx * STEP + 1..=(n - 1) as usize { fac *= i as i64; } ans *= fac; println!("{ans}"); }