結果

問題 No.121 傾向と対策：門松列（その２）
コンテスト
ユーザー heno239
提出日時 2020-08-03 17:50:25
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 1,772 ms / 5,000 ms
コード長 4,033 bytes
コンパイル時間 1,582 ms
コンパイル使用メモリ 127,360 KB
実行使用メモリ 112,748 KB
最終ジャッジ日時 2024-09-13 11:32:28
合計ジャッジ時間 7,555 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge1
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ファイルパターン 結果
other AC * 9
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ソースコード

diff #
raw source code 

#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 998244353;
const ll INF = mod * mod;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);

ll mod_pow(ll x, ll n, ll m) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n % mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

const int max_n = 1 << 18;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}

struct BIT {
private:
	vector<ll> node; int n;
public:
	BIT(int n_) {
		n = n_; node.resize(n, 0);
	}
	//0-indexed
	void add(int a, ll w) {
		for (int i = a; i < n; i |= i + 1)node[i] += w;
	}
	//[0,a)
	ll sum(int a) {
		ll ret = 0;
		for (int i = a - 1; i >= 0; i = (i & (i + 1)) - 1)ret += node[i];
		return ret;
	}
	//[a,b)
	ll sum(int a, int b) {
		return sum(b) - sum(a);
	}
};



ll calc(vector<int> v,int sup) {
	int n = v.size();
	BIT btle(sup);
	vector<ll> le(n), ri(n);
	rep(i, n) {
		le[i] = btle.sum(v[i]);
		btle.add(v[i], 1);
	}
	BIT btri(sup);
	per(i, n) {
		ri[i] = btri.sum(v[i]);
		btri.add(v[i], 1);
	}
	ll ans = 0;
	rep(i, n)ans += le[i] * ri[i];
	vector<vector<int>> loc(sup);
	rep(i, n)loc[v[i]].push_back(i);
	BIT bt(n);
	per(i, sup) {
		int sz = loc[i].size();
		rep(j, sz - 1) {
			ll cl = j + 1;
			ll cr = sz - j-1;
			ll num = bt.sum(loc[i][j], loc[i][j + 1]);
			ans -= cl * cr * num;
		}

		for (int id : loc[i])bt.add(id, 1);
	}
	return ans;
}
void solve() {
	int n; cin >> n;
	vector<int> a(n);
	rep(i, n)cin >> a[i];
	vector<int> cop = a;
	sort(all(cop));
	cop.erase(unique(all(cop)), cop.end());
	int sup = cop.size();
	rep(i, n) {
		a[i] = lower_bound(all(cop), a[i]) - cop.begin();
	}
	ll ans = calc(a, sup);
	rep(i, a.size())a[i] = sup - 1 - a[i];
	ans += calc(a, sup);
	cout << ans << "\n";
}




signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(10);
	//init_f();
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}
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