結果

問題 No.1300 Sum of Inversions
ユーザー nok0nok0
提出日時 2020-11-23 23:02:50
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 112 ms / 2,000 ms
コード長 4,360 bytes
コンパイル時間 2,481 ms
コンパイル使用メモリ 212,060 KB
実行使用メモリ 9,644 KB
最終ジャッジ日時 2024-07-23 18:04:59
合計ジャッジ時間 8,269 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
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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 2 ms
6,812 KB
testcase_01 AC 2 ms
6,940 KB
testcase_02 AC 2 ms
6,940 KB
testcase_03 AC 87 ms
8,192 KB
testcase_04 AC 84 ms
8,080 KB
testcase_05 AC 69 ms
7,424 KB
testcase_06 AC 96 ms
8,740 KB
testcase_07 AC 94 ms
8,576 KB
testcase_08 AC 103 ms
9,088 KB
testcase_09 AC 102 ms
8,932 KB
testcase_10 AC 56 ms
6,944 KB
testcase_11 AC 57 ms
6,940 KB
testcase_12 AC 84 ms
7,980 KB
testcase_13 AC 82 ms
8,132 KB
testcase_14 AC 112 ms
9,568 KB
testcase_15 AC 106 ms
8,832 KB
testcase_16 AC 89 ms
8,320 KB
testcase_17 AC 54 ms
6,940 KB
testcase_18 AC 64 ms
6,940 KB
testcase_19 AC 76 ms
7,568 KB
testcase_20 AC 78 ms
7,680 KB
testcase_21 AC 77 ms
7,680 KB
testcase_22 AC 69 ms
7,296 KB
testcase_23 AC 95 ms
8,736 KB
testcase_24 AC 71 ms
7,424 KB
testcase_25 AC 60 ms
6,944 KB
testcase_26 AC 59 ms
6,944 KB
testcase_27 AC 66 ms
7,040 KB
testcase_28 AC 107 ms
9,216 KB
testcase_29 AC 73 ms
7,744 KB
testcase_30 AC 103 ms
9,056 KB
testcase_31 AC 68 ms
7,296 KB
testcase_32 AC 72 ms
7,424 KB
testcase_33 AC 31 ms
8,064 KB
testcase_34 AC 42 ms
8,192 KB
testcase_35 AC 70 ms
9,640 KB
testcase_36 AC 73 ms
9,644 KB
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ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;

template <const int &mod>
struct ModInt {
private:
	int x;

public:
	ModInt() : x(0) {}

	ModInt(long long x_) {
		if((x = x_ % mod + mod) >= mod) x -= mod;
	}

	int val() const { return x; }

	static int get_mod() { return mod; }

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

	constexpr ModInt &operator-=(ModInt rhs) {
		if((x -= rhs.x) < 0) x += mod;
		return *this;
	}

	constexpr ModInt &operator*=(ModInt rhs) {
		x = (unsigned long long)x * rhs.x % mod;
		return *this;
	}

	constexpr ModInt &operator/=(ModInt rhs) {
		x = (unsigned long long)x * rhs.inv().x % mod;
		return *this;
	}

	constexpr ModInt operator-() const noexcept { return -x < 0 ? mod - x : -x; }

	constexpr ModInt operator+(ModInt rhs) const noexcept { return ModInt(*this) += rhs; }

	constexpr ModInt operator-(ModInt rhs) const noexcept { return ModInt(*this) -= rhs; }

	constexpr ModInt operator*(ModInt rhs) const noexcept { return ModInt(*this) *= rhs; }

	constexpr ModInt operator/(ModInt rhs) const noexcept { return ModInt(*this) /= rhs; }

	constexpr ModInt &operator++() {
		*this += 1;
		return *this;
	}

	constexpr ModInt operator++(int) {
		*this += 1;
		return *this - 1;
	}

	constexpr ModInt &operator--() {
		*this -= 1;
		return *this;
	}

	constexpr ModInt operator--(int) {
		*this -= 1;
		return *this + 1;
	}

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

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

	bool operator<=(ModInt rhs) const { return x <= rhs.x; }

	bool operator>=(ModInt rhs) const { return x >= rhs.x; }

	bool operator<(ModInt rhs) const { return x < rhs.x; }

	bool operator>(ModInt rhs) const { return x > rhs.x; }

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

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

	ModInt sqrt() const {
		if(x <= 1) return x;
		int v = (mod - 1) / 2;
		if(pow(v) != 1) return -1;
		int q = mod - 1, m = 0;
		while(~q & 1) q >>= 1, m++;
		std::mt19937 mt;
		ModInt z = mt();
		while(z.pow(v) != mod - 1) z = mt();
		ModInt c = z.pow(q), t = pow(q), r = pow((q + 1) / 2);
		for(; m > 1; m--) {
			ModInt tmp = t.pow(1 << (m - 2));
			if(tmp != 1) r = r * c, t = t * c * c;
			c = c * c;
		}
		return std::min(r.x, mod - r.x);
	}

	friend std::ostream &operator<<(std::ostream &s, ModInt<mod> a) {
		s << a.x;
		return s;
	}

	friend std::istream &operator>>(std::istream &s, ModInt<mod> &a) {
		s >> a.x;
		return s;
	}
};
constexpr static int MOD = 998244353;
using mint = ModInt<MOD>;

template <typename T>
struct BIT {
private:
	int n, p;
	std::vector<T> d;

public:
	BIT() = default;

	BIT(int n) : n(n), d(n + 1) {
		p = 1;
		while(p < n) p *= 2;
	}

	void add(int i, T x = 1) {
		for(i++; i <= n; i += i & -i) d[i] += x;
	}

	//return sum[0,i)
	T sum(int i) {
		T res = 0;
		for(; i; i -= i & -i) res += d[i];
		return res;
	}

	//return sum[l,r)
	T sum(int l, int r) { return sum(r) - sum(l); }
};

template <class T>
std::vector<T> press(std::vector<T> &x) {
	auto res = x;
	std::sort(res.begin(), res.end());
	res.erase(std::unique(res.begin(), res.end()), res.end());
	for(int i = 0; i < (int)x.size(); i++)
		x[i] = std::lower_bound(res.begin(), res.end(), x[i]) - res.begin();
	return res;
}

mint res;
int main() {
	//入力受け取り
	int n;
	scanf("%d", &n);

	vector a(n, 0);
	for(auto &v : a) scanf("%d", &v);

	//座標圧縮
	auto rec = press(a);
	int m = rec.size();

	//以下は前準備
	vector<mint> x(n), y(n);
	vector<int> l(n), r(n);

	{
		BIT<mint> BT(m);
		BIT<int> kosuu(m);
		for(int i = 0; i < n; i++) {
			BT.add(a[i], rec[a[i]]);
			kosuu.add(a[i], 1);
			x[i] = BT.sum(a[i] + 1, m);
			l[i] = kosuu.sum(a[i] + 1, m);
		}
	}

	{
		BIT<mint> BT(m);
		BIT<int> kosuu(m);
		for(int i = n - 1; i >= 0; i--) {
			BT.add(a[i], rec[a[i]]);
			kosuu.add(a[i], 1);
			y[i] = BT.sum(0, a[i]);
			r[i] = kosuu.sum(0, a[i]);
		}
	}

	//答えの計算
	for(int j = 0; j < n; j++) {
		if(!l[j] * r[j]) continue;
		mint tmp = rec[a[j]];
		res += x[j] * r[j] + y[j] * l[j] + tmp * l[j] * r[j];
	}

	cout << res << endl;

	return 0;
}
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