Submission #234124

#	Time	Username	Problem	Language	Result	Execution time	Memory
234124		anubhavdhar	Mountains (NOI20_mountains)	C++14	100 / 100	298 ms	20088 KiB

Mountains

#include<bits/stdc++.h>

#define ll long long
#define int ll
#define pb push_back
#define mp make_pair
#define FOR(i,n) for(i=0;i<(n);++i)
#define FORe(i,n) for(i=1;i<=(n);++i)
#define FORr(i,a,b) for(i=(a);i<(b);++i)
#define FORrev(i,n) for(i=(n);i>=0;--i)
#define F0R(i,n) for(int i=0;i<(n);++i)
#define F0Re(i,n) for(int i=1;i<=(n);++i)
#define F0Rr(i,a,b) for(ll i=(a);i<(b);++i)
#define F0Rrev(i,n) for(int i=(n);i>=0;--i)
#define ii pair<ll,ll>
#define vi vector<ll>
#define vii vector<ii>
#define ff first 
#define ss second
#define cd complex<double>
#define vcd vector<cd>
#define ldd long double
#define dbgLine cout<<"Line : "<<__LINE__<<'\n'
#define all(x) (x).begin(),(x).end()

using namespace std;

const int __PRECISION = 10;

const ll MOD = 1e9+7;
const ll INF = 1e17 + 1101;
const ll LOGN = 17;
const ll MAXN = 3e5+5;
const ll ROOTN = 320;

const ldd PI = acos(-1);
const ldd EPS = 1e-7;

struct SegTree
{
	int st[4*MAXN];

	void upd(int node, int ss, int se, int i)
	{
		if(ss >  i or se < i)
			return;
		if(ss == se)
		{
			++st[node];
			return;
		}
		int mid = (ss + se)/2;
		upd(node*2 + 1, ss, mid, i);
		upd(node*2 + 2, mid+1, se, i);
		st[node] = st[node*2+1] + st[node*2+2];
	}

	ll quer(int node, int ss, int se, int l, int r)
	{
		if(ss > r or se < l)	return 0;
		if(ss >= l and se <= r)	return st[node];
		int mid = (ss + se) / 2;
		return quer(node*2+1, ss, mid,l,r) + quer(node*2+2,mid+1,se,l,r);
	}

	SegTree()
	{
		F0R(i, 4*MAXN)
			st[i] = 0;
	}

	inline void update(int i)
	{
		upd(0, 0, MAXN, i);
	}

	inline ll query(int i, int ded)
	{
		ll a = quer(0, 0, MAXN, 0, i-1) - ded, b = quer(0, 0, MAXN, i+1, MAXN);
		// cout<<"a = "<<a<<", b = "<<b<<'\n';
		return (a*b);
	}
} S;

signed main()
{
	
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	
	int N;
	cin>>N;
	pair<ll, int> A[N];
	F0R(i, N)
	{
		ll j;
		cin>>j;
		A[i] = mp(j, i+1);
	}
	sort(A, A + N);
	ll previo = -1, tot = 0, ans = 0;
	F0R(i, N)
	{
		// cout<<"for ("<<A[i].ff<<','<<A[i].ss<<") : ";
		if(A[i].ff != previo)
			tot = 0;
		S.update(A[i].ss);
		int tmp = S.query(A[i].ss, tot);
		// cout<<"tot = "<<tot<<", previo = "<<previo<<", no. of combinations is "<<tmp<<'\n';
		previo = A[i].ff;
		++tot;
		ans += tmp;
	}
	cout<<ans;
	return 0;
}

• Subtask 1: 2 / 2
• Subtask 2: 4 / 4
• Subtask 3: 9 / 9
• Subtask 4: 36 / 36
• Subtask 5: 28 / 28
• Subtask 6: 9 / 9
• Subtask 7: 12 / 12