結果

問題 No.1621 Sequence Inversions
ユーザー torisasami4torisasami4
提出日時 2021-07-22 22:42:25
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 248 ms / 3,000 ms
コード長 8,467 bytes
コンパイル時間 2,086 ms
コンパイル使用メモリ 189,808 KB
実行使用メモリ 200,704 KB
最終ジャッジ日時 2024-07-17 19:01:46
合計ジャッジ時間 5,068 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge2
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
5,248 KB
testcase_01 AC 2 ms
5,376 KB
testcase_02 AC 2 ms
5,376 KB
testcase_03 AC 4 ms
5,376 KB
testcase_04 AC 94 ms
70,784 KB
testcase_05 AC 2 ms
5,376 KB
testcase_06 AC 1 ms
5,376 KB
testcase_07 AC 6 ms
6,272 KB
testcase_08 AC 105 ms
77,440 KB
testcase_09 AC 137 ms
102,784 KB
testcase_10 AC 243 ms
200,704 KB
testcase_11 AC 115 ms
84,736 KB
testcase_12 AC 241 ms
195,968 KB
testcase_13 AC 248 ms
197,504 KB
testcase_14 AC 48 ms
28,908 KB
testcase_15 AC 47 ms
20,808 KB
testcase_16 AC 94 ms
58,684 KB
testcase_17 AC 167 ms
112,000 KB
testcase_18 AC 91 ms
55,036 KB
testcase_19 AC 3 ms
5,376 KB
testcase_20 AC 36 ms
26,712 KB
testcase_21 AC 188 ms
128,488 KB
testcase_22 AC 69 ms
33,664 KB
testcase_23 AC 217 ms
154,448 KB
testcase_24 AC 2 ms
5,376 KB
testcase_25 AC 2 ms
5,376 KB
testcase_26 AC 2 ms
5,376 KB
testcase_27 AC 2 ms
5,376 KB
testcase_28 AC 2 ms
5,376 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb(x) push_back(x)
#define mp(a, b) make_pair(a, b)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define lscan(x) scanf("%I64d", &x)
#define lprint(x) printf("%I64d", x)
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define rep2(i, n) for (ll i = (ll)n - 1; i >= 0; i--)
#define REP(i, l, r) for (ll i = l; i < (r); i++)
#define REP2(i, l, r) for (ll i = (ll)r - 1; i >= (l); i--)
#define siz(x) (ll)x.size()
template <class T>
using rque = priority_queue<T, vector<T>, greater<T>>;
const ll mod = 998244353;

template <class T>
bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return 1;
    }
    return 0;
}

template <class T>
bool chmax(T &a, const T &b) {
    if (b > a) {
        a = b;
        return 1;
    }
    return 0;
}

ll gcd(ll a, ll b)
{
	if(a == 0)
		return b;
	if(b == 0)
		return a;
	ll cnt = a % b;
	while (cnt != 0)
	{
		a = b;
		b = cnt;
		cnt = a % b;
	}
	return b;
}

long long extGCD(long long a, long long b, long long &x, long long &y)
{
	if (b == 0)
	{
		x = 1;
		y = 0;
		return a;
	}
	long long d = extGCD(b, a % b, y, x);
	y -= a / b * x;
	return d;
}

struct UnionFind
{
	vector<ll> data;
	int num;

	UnionFind(int sz)
	{
		data.assign(sz, -1);
		num = sz;
	}

	bool unite(int x, int y)
	{
		x = find(x), y = find(y);
		if (x == y)
			return (false);
		if (data[x] > data[y])
			swap(x, y);
		data[x] += data[y];
		data[y] = x;
		num--;
		return (true);
	}

	int find(int k)
	{
		if (data[k] < 0)
			return (k);
		return (data[k] = find(data[k]));
	}

	ll size(int k)
	{
		return (-data[find(k)]);
	}

	bool same(int x, int y){
		return find(x) == find(y);
	}
};

ll M = 1000000007;

template <int mod>
struct ModInt
{
	int x;

	ModInt() : x(0) {}

	ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

	ModInt &operator+=(const ModInt &p)
	{
		if ((x += p.x) >= mod)
			x -= mod;
		return *this;
	}

	ModInt &operator-=(const ModInt &p)
	{
		if ((x += mod - p.x) >= mod)
			x -= mod;
		return *this;
	}

	ModInt &operator*=(const ModInt &p)
	{
		x = (int)(1LL * x * p.x % mod);
		return *this;
	}

	ModInt &operator/=(const ModInt &p)
	{
		*this *= p.inverse();
		return *this;
	}

	ModInt operator-() const { return ModInt(-x); }

	ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

	ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

	ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

	ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

	bool operator==(const ModInt &p) const { return x == p.x; }

	bool operator!=(const ModInt &p) const { return x != p.x; }

	ModInt inverse() const
	{
		int a = x, b = mod, u = 1, v = 0, t;
		while (b > 0)
		{
			t = a / b;
			swap(a -= t * b, b);
			swap(u -= t * v, v);
		}
		return ModInt(u);
	}

	ModInt pow(int64_t n) const
	{
		ModInt ret(1), mul(x);
		while (n > 0)
		{
			if (n & 1)
				ret *= mul;
			mul *= mul;
			n >>= 1;
		}
		return ret;
	}

	friend ostream &operator<<(ostream &os, const ModInt &p)
	{
		return os << p.x;
	}

	friend istream &operator>>(istream &is, ModInt &a)
	{
		int64_t t;
		is >> t;
		a = ModInt<mod>(t);
		return (is);
	}

	static int get_mod() { return mod; }
};

using mint = ModInt<mod>;

mint mpow(mint x, ll n)
{
	mint ans = 1;
	while (n != 0)
	{
		if (n & 1)
			ans *= x;
		x *= x;
		n = n >> 1;
	}
	return ans;
}

ll mpow2(ll x, ll n, ll mod)
{
	ll ans = 1;
	while (n != 0)
	{
		if (n & 1)
			ans = ans * x % mod;
		x = x * x % mod;
		n = n >> 1;
	}
	return ans;
}

vector<mint> fac;
vector<mint> ifac;

void setcomb(int sz = 2000010)
{
	fac.assign(sz + 1, 0);
	ifac.assign(sz + 1, 0);
	fac[0] = 1;
	for (ll i = 0; i < sz; i++)
	{
		fac[i + 1] = fac[i] * (i + 1); // n!(mod M)
	}
	ifac[sz] = fac[sz].inverse();
	for (ll i = sz; i > 0; i--)
	{
		ifac[i - 1] = ifac[i] * i;
	}
}
mint comb(ll a, ll b)
{
	if(fac.size() == 0)
		setcomb();
	if (a == 0 && b == 0)
		return 1;
	if (a < b || a < 0 || b < 0)
		return 0;
	return ifac[a - b] * ifac[b] * fac[a];
}

mint perm(ll a, ll b)
{
	if(fac.size() == 0)
		setcomb();
	if (a == 0 && b == 0)
		return 1;
	if (a < b || a < 0)
		return 0;
	return fac[a] * ifac[a - b];
}

long long modinv(long long a)
{
	long long b = M, u = 1, v = 0;
	while (b)
	{
		long long t = a / b;
		a -= t * b;
		swap(a, b);
		u -= t * v;
		swap(u, v);
	}
	u %= M;
	if (u < 0)
		u += M;
	return u;
}

ll modinv2(ll a, ll mod)
{
	ll b = mod, u = 1, v = 0;
	while (b)
	{
		ll t = a / b;
		a -= t * b;
		swap(a, b);
		u -= t * v;
		swap(u, v);
	}
	u %= mod;
	if (u < 0)
		u += mod;
	return u;
}

template <int mod>
struct NumberTheoreticTransform
{

    vector<int> rev, rts;
    int base, max_base, root;

    NumberTheoreticTransform() : base(1), rev{0, 1}, rts{0, 1}
    {
        assert(mod >= 3 && mod % 2 == 1);
        auto tmp = mod - 1;
        max_base = 0;
        while (tmp % 2 == 0)
            tmp >>= 1, max_base++;
        root = 2;
        while (mod_pow(root, (mod - 1) >> 1) == 1)
            ++root;
        assert(mod_pow(root, mod - 1) == 1);
        root = mod_pow(root, (mod - 1) >> max_base);
    }

    inline int mod_pow(int x, int n)
    {
        int ret = 1;
        while (n > 0)
        {
            if (n & 1)
                ret = mul(ret, x);
            x = mul(x, x);
            n >>= 1;
        }
        return ret;
    }

    inline int inverse(int x)
    {
        return mod_pow(x, mod - 2);
    }

    inline unsigned add(unsigned x, unsigned y)
    {
        x += y;
        if (x >= mod)
            x -= mod;
        return x;
    }

    inline unsigned mul(unsigned a, unsigned b)
    {
        return 1ull * a * b % (unsigned long long)mod;
    }

    void ensure_base(int nbase)
    {
        if (nbase <= base)
            return;
        rev.resize(1 << nbase);
        rts.resize(1 << nbase);
        for (int i = 0; i < (1 << nbase); i++)
        {
            rev[i] = (rev[i >> 1] >> 1) + ((i & 1) << (nbase - 1));
        }
        assert(nbase <= max_base);
        while (base < nbase)
        {
            int z = mod_pow(root, 1 << (max_base - 1 - base));
            for (int i = 1 << (base - 1); i < (1 << base); i++)
            {
                rts[i << 1] = rts[i];
                rts[(i << 1) + 1] = mul(rts[i], z);
            }
            ++base;
        }
    }

    void ntt(vector<mint> &a)
    {
        const int n = (int)a.size();
        assert((n & (n - 1)) == 0);
        int zeros = __builtin_ctz(n);
        ensure_base(zeros);
        int shift = base - zeros;
        for (int i = 0; i < n; i++)
        {
            if (i < (rev[i] >> shift))
            {
                swap(a[i], a[rev[i] >> shift]);
            }
        }
        for (int k = 1; k < n; k <<= 1)
        {
            for (int i = 0; i < n; i += 2 * k)
            {
                for (int j = 0; j < k; j++)
                {
                    mint z = a[i + j + k] * rts[j + k];
                    a[i + j + k] = a[i + j] - z;
                    a[i + j] = a[i + j] + z;
                }
            }
        }
    }

    vector<mint> multiply(vector<mint> a, vector<mint> b)
    {
        int need = a.size() + b.size() - 1;
        int nbase = 1;
        while ((1 << nbase) < need)
            nbase++;
        ensure_base(nbase);
        int sz = 1 << nbase;
        a.resize(sz, 0);
        b.resize(sz, 0);
        ntt(a);
        ntt(b);
        mint inv_sz = inverse(sz);
        for (int i = 0; i < sz; i++)
        {
            a[i] = a[i] * b[i] * inv_sz;
        }
        reverse(a.begin() + 1, a.end());
        ntt(a);
        a.resize(need);
        return a;
    }
};
using NTT = NumberTheoreticTransform<mod>;

int main(){
	ios::sync_with_stdio(false);
	std::cin.tie(nullptr);

	ll n, k;
	cin >> n >> k;
	ll a[n];
	rep(i, n) cin >> a[i];
	map<ll, ll> cnt;
	rep(i, n) cnt[a[i]]++;
	mint dp[n + 1][k + 1][n + 1] = {};
	rep(t, n + 1) dp[0][0][t] = 1;
	REP(i,1,n+1)rep(j,k+1)rep(t,n+1){
		if(j == 0){
			dp[i][j][t] = 1;
			continue;
		}
		if(t == 0)
			continue;
		dp[i][j][t] = dp[i][j][t - 1];
		if(j >= t)
			dp[i][j][t] += dp[i - 1][j - t][t];
	}
	NTT ntt;
	vector<mint> d(1, 1);
	ll sum = 0;
	for(auto e: cnt){
		ll ncnt = e.second;
		vector<mint> nd(min(k, sum * ncnt) + 1);
		rep(i, nd.size()) nd[i] = dp[ncnt][i][sum];
		d = ntt.multiply(d, nd);
		sum += ncnt;
	}
	cout << (d.size() > k ? d[k] : 0) << endl;
}
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