結果
| 問題 | No.1392 Don't be together |
| ユーザー |
 emthrm
|
| 提出日時 | 2021-02-12 22:17:28 |
| 言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
AC
|
| 実行時間 | 884 ms / 2,000 ms |
| コード長 | 5,647 bytes |
| コンパイル時間 | 2,986 ms |
| コンパイル使用メモリ | 205,604 KB |
| 最終ジャッジ日時 | 2025-01-18 18:49:27 |
|
ジャッジサーバーID （参考情報） |
judge2 / judge1 |
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| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 27 |
ソースコード
#define _USE_MATH_DEFINES#include <bits/stdc++.h>using namespace std;#define FOR(i,m,n) for(int i=(m);i<(n);++i)#define REP(i,n) FOR(i,0,n)#define ALL(v) (v).begin(),(v).end()using ll = long long;constexpr int INF = 0x3f3f3f3f;constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;constexpr double EPS = 1e-8;constexpr int MOD = 998244353;constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }struct IOSetup {IOSetup() {std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false);std::cout << fixed << setprecision(20);}} iosetup;template <int MOD>struct MInt {unsigned val;MInt(): val(0) {}MInt(long long x) : val(x >= 0 ? x % MOD : x % MOD + MOD) {}static int get_mod() { return MOD; }static void set_mod(int divisor) { assert(divisor == MOD); }MInt pow(long long exponent) const {MInt tmp = *this, res = 1;while (exponent > 0) {if (exponent & 1) res *= tmp;tmp *= tmp;exponent >>= 1;}return res;}MInt &operator+=(const MInt &x) { if((val += x.val) >= MOD) val -= MOD; return *this; }MInt &operator-=(const MInt &x) { if((val += MOD - x.val) >= MOD) val -= MOD; return *this; }MInt &operator*=(const MInt &x) { val = static_cast<unsigned long long>(val) * x.val % MOD; return *this; }MInt &operator/=(const MInt &x) {// assert(std::__gcd(static_cast<int>(x.val), MOD) == 1);unsigned a = x.val, b = MOD; int u = 1, v = 0;while (b) {unsigned tmp = a / b;std::swap(a -= tmp * b, b);std::swap(u -= tmp * v, v);}return *this *= u;}bool operator==(const MInt &x) const { return val == x.val; }bool operator!=(const MInt &x) const { return val != x.val; }bool operator<(const MInt &x) const { return val < x.val; }bool operator<=(const MInt &x) const { return val <= x.val; }bool operator>(const MInt &x) const { return val > x.val; }bool operator>=(const MInt &x) const { return val >= x.val; }MInt &operator++() { if (++val == MOD) val = 0; return *this; }MInt operator++(int) { MInt res = *this; ++*this; return res; }MInt &operator--() { val = (val == 0 ? MOD : val) - 1; return *this; }MInt operator--(int) { MInt res = *this; --*this; return res; }MInt operator+() const { return *this; }MInt operator-() const { return MInt(val ? MOD - val : 0); }MInt operator+(const MInt &x) const { return MInt(*this) += x; }MInt operator-(const MInt &x) const { return MInt(*this) -= x; }MInt operator*(const MInt &x) const { return MInt(*this) *= x; }MInt operator/(const MInt &x) const { return MInt(*this) /= x; }friend std::ostream &operator<<(std::ostream &os, const MInt &x) { return os << x.val; }friend std::istream &operator>>(std::istream &is, MInt &x) { long long val; is >> val; x = MInt(val); return is; }};namespace std { template <int MOD> MInt<MOD> abs(const MInt<MOD> &x) { return x; } }template <int MOD>struct Combinatorics {using ModInt = MInt<MOD>;int val; // "val!" and "mod" must be disjoint.std::vector<ModInt> fact, fact_inv, inv;Combinatorics(int val = 10000000) : val(val), fact(val + 1), fact_inv(val + 1), inv(val + 1) {fact[0] = 1;for (int i = 1; i <= val; ++i) fact[i] = fact[i - 1] * i;fact_inv[val] = ModInt(1) / fact[val];for (int i = val; i > 0; --i) fact_inv[i - 1] = fact_inv[i] * i;for (int i = 1; i <= val; ++i) inv[i] = fact[i - 1] * fact_inv[i];}ModInt nCk(int n, int k) const {if (n < 0 || n < k || k < 0) return 0;assert(n <= val && k <= val);return fact[n] * fact_inv[k] * fact_inv[n - k];}ModInt nPk(int n, int k) const {if (n < 0 || n < k || k < 0) return 0;assert(n <= val);return fact[n] * fact_inv[n - k];}ModInt nHk(int n, int k) const {if (n < 0 || k < 0) return 0;return k == 0 ? 1 : nCk(n + k - 1, k);}};using ModInt = MInt<MOD>;struct UnionFind {UnionFind(int n) : data(n, -1) {}int root(int ver) { return data[ver] < 0 ? ver : data[ver] = root(data[ver]); }bool unite(int u, int v) {u = root(u);v = root(v);if (u == v) return false;if (data[u] > data[v]) std::swap(u, v);data[u] += data[v];data[v] = u;return true;}bool same(int u, int v) { return root(u) == root(v); }int size(int ver) { return -data[root(ver)]; }private:std::vector<int> data;};int main() {int n, m; cin >> n >> m;UnionFind uf(n);REP(i, n) {int p; cin >> p; --p;uf.unite(i, p);}vector<int> cycle;REP(i, n) {if (uf.root(i) == i) cycle.emplace_back(uf.size(i));}vector<ModInt> dp(m + 1, 0);dp[0] = 1;for (int len : cycle) {vector tmp(2, vector(m + 1, ModInt(0)));REP(j, m + 1) {tmp[true][j] += dp[j] * j;if (j + 1 <= m) tmp[true][j + 1] += dp[j] * (m - j);}FOR(i, 1, len) {vector nx(2, vector(m + 1, ModInt(0)));FOR(j, 1, m + 1) {nx[false][j] += tmp[true][j] * (j - 1);if (j + 1 <= m) nx[false][j + 1] += tmp[true][j] * (m - j);nx[true][j] += tmp[false][j];nx[false][j] += tmp[false][j] * max(j - 2, 0);if (j + 1 <= m) nx[false][j + 1] += tmp[false][j] * (m - j);}tmp.swap(nx);}REP(j, m + 1) dp[j] = tmp[false][j];}cout << dp[m] * Combinatorics<MOD>().fact_inv[m] << '\n';return 0;}