Submission #1124090

#	Time	Username	Problem	Language	Result	Execution time	Memory
1124090		tintingyn21	Mountains (NOI20_mountains)	C++20	0 / 100	11 ms	1628 KiB

Mountains

// author : daohuyenchi



#ifdef LOCAL
    #include "D:\C++ Submit\debug.h"
#else
    #define debug(...)
#endif



#include <bits/stdc++.h>

using namespace std;

#define ull unsigned long long
#define db double
#define i32 int32_t
#define i64 int64_t
#define ll long long
//
#define fi first
#define se second


//                                      #define int long long    // consider carefully


//
#define pii pair <int, int>
#define pll pair <ll, ll>
#define PAIR make_pair
#define TUP make_tuple
//                                      TIME IS LIMITED ...
#define  rep(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define repd(i, b, a) for (int i = (b), _a = (a); i >= _a; --i)
#define repv(v, H) for(auto &v: H)
//                                      REFLECT ON THE PAST ...
#define RESET(c, x) memset(c, x, sizeof(c))
#define MASK(i) (1LL << (i))
#define BIT(mask, i) (((mask) >> (i)) & 1LL)
#define ONBIT(mask, i) ((mask) | (1LL << (i)))
#define OFFBIT(mask, i) ((mask) &~ (1LL << (i)))
#define COUNTBIT __builtin_popcountll
//                                      30 / 1 / 2024 ? love is zero... start from zero
#define vi vector <int>
#define vll vector <ll>
#define Lower lower_bound
#define Upper upper_bound
#define all(v) (v).begin(), (v).end()
#define special(H) (H).resize(distance(H.begin(), unique(all(H))))
//
#define sp ' '
#define nl '\n'
#define EL { cerr << '\n'; }
#define yes "YES"
#define no "NO"
#define Log2(n) (63 - __builtin_clzll(n))
#define left __left__
#define right __right__
#define lps(id) ((id) << 1)
#define rps(id) ((id) << 1 | 1)

//____________________________________________________________________


template <class X, class Y> bool maximize(X &a, const Y &b)
{ if(a < b) return a = b, true; else return false; }

template <class X, class Y> bool minimize(X &a, const Y &b)
{ if(a > b) return a = b, true; else return false; }

template <class... T>
void print(T&&... n)
{ using exp = int[]; exp{ 0, (cerr << n << sp, 0)... }; cerr << nl; }

template <class T, class... C>
void assign(int n, T v, C&&... a)
{ using e = int[]; e { (a.assign(n, v), 0)...}; }

template <class... C>
void resize(int n, C&&... a)
{ using e = int[]; e { (a.resize(n), 0)...}; }

template <class T>
using vector2d = vector<vector<T>>;
template <class T>
using vector3d = vector<vector2d<T>>;

template <class T> int ssize(T &a) { return (int) a.size(); }


//____________________________________________________________________


mt19937 rng(chrono::steady_clock().now().time_since_epoch().count());

const long long MOD      = 1000000007;
// const int MOD[2] = {1000000009, 998244353};

template<class X> void modmize(X &x, long long cur_Mod = MOD) {
    if(x >= cur_Mod) x -= cur_Mod;
    if(x < 0) x += cur_Mod;
}

int mod_plus(int A, int B) { modmize(A += B); return A; }

const long long oo      = 1e18 + 7;
const long long LINF    = 1e18 + 7;
const int IINF          = 2e9;
const int nmax          = 2e5 + 10;
const int MAX           = 1e6;
const int base          = 311;
const double eps        = 1e-6;
const int block         = 500;
static const double PI  = acos(-1.0);

//____________________________________________________________________


int n;
int h[nmax];




struct Fenwick {
    vector <int> bit;
    int Lim;

    Fenwick() {}
    Fenwick(int _n) {
        bit.assign(_n + 1, 0);
        Lim = _n;
    }

    void Assign(int _n) {
        bit.assign(_n + 1, 0);
        Lim = _n;
    }

    void Init() {
        rep (i, 1, Lim) {
            bit[i] = 0;
        }
    }

    void upd(int i, int val) {
        for (; i <= Lim; i += i & -i) bit[i] += val;
    }

    int get_pt(int i) {
        int cur = 0;
        for (; i > 0; i -= i & -i) cur += bit[i];
        return cur;
    }

    int get_rn(int l, int r) {
        return get_pt(r) - get_pt(l - 1);
    }
} ;



void tintingyn()
{

	cin >> n;
	rep (i, 1, n) {
		cin >> h[i];
	}

	vector <int> ord(n + 1);
	rep (i, 1, n) {
		ord[i] = i;
	}
	sort(ord.begin() + 1, ord.begin() + n + 1, [&] (int x, int y) {
		return h[x] < h[y];

		}) ;

	ll ans = 0;

	Fenwick fen(n);

	rep (_i, 1, n) {
		int i = ord[_i];

		int j = _i;
		for (; j < n; ) {
			if (h[ord[j + 1]] == h[i]) ++j;
			else break;
		}

		rep (t, _i, j) {
			int p = ord[t];
			ans += (ll) fen.get_rn(1, p - 1) * fen.get_rn(p + 1, n);
		}

		rep (t, _i, j) {
			int p = ord[t];
			fen.upd(p, 1);
		}

		_i = j;
	}

	cout << ans << nl;

}

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    //________________________________________________________________

    #define TASK "1"
    if(fopen(TASK".inp", "r"))
    { freopen(TASK".inp", "r", stdin); freopen(TASK".out", "w", stdout); }

    //________________________________________________________________

    //  CODE FROM HERE ...!





    int num_test = 1;
    // cin >> num_test;

    while(num_test--) {

        tintingyn();

    }


    cerr << '\n' << "Time elapsed: " << (1.0 * clock() / CLOCKS_PER_SEC) << " s\n" << nl;

    return 0;
}

Compilation message (stderr)

Mountains.cpp: In function 'int main()':
Mountains.cpp:224:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  224 |     { freopen(TASK".inp", "r", stdin); freopen(TASK".out", "w", stdout); }
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Mountains.cpp:224:47: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  224 |     { freopen(TASK".inp", "r", stdin); freopen(TASK".out", "w", stdout); }
      |                                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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