Submission #224860

#	Time	Username	Problem	Language	Result	Execution time	Memory
224860		bukanYohandi	Mountains (NOI20_mountains)	C++14	100 / 100	267 ms	33528 KiB

Mountains

 	#include <bits/stdc++.h>

#define fs first
#define sc second
#define pb push_back
#define eb emplace_back

#define all(a) a.begin(),a.end()
#define lb(a,x) (lower_bound(all(a),x)-a.begin())
#define ub(a,x) (upper_bound(all(a),x)-a.begin())

#define rep(a,x,y) for(int a=(int)x;a<=(int)y;++a)
#define repd(a,x,y,d) for(int a=(int)x;a<=(int)y;a+=d)
#define res(a,x,y) for(int a=(int)x;a>=(int)y;--a)
#define resd(a,x,y,d) for(int a=(int)x;a>=(int)y;a-=d)

// Ordered Set, Ordered Multiset
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define o_set tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>
#define o_multiset tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>
using namespace __gnu_pbds;
// .order_of_key(x) -> Number of elements less than x
// * .find_by_order(k) -> Kth smallest element (0-based)
// .erase(x) -> Remove all elements equal to x

#pragma GCC optimize("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

using namespace std;
using lint=long long;

mt19937 rng(time(NULL));

lint Power(lint A,lint B,lint C){
	if(!B) return 1LL;
	lint tmp=Power(A,B>>1,C);
	return tmp*tmp%C*(B&1?A:1)%C;
}

struct Q{lint L,R,Idx,X;};
struct Smth{lint Idx,Val;} Arr[333333];

int T,N;
lint Ans,Le,Ri;
lint Bit[333333],H[333333],Prefix[111][333333];
lint Jwb[666666];
Q Query[666666];

lint Sum(int Idx){
    lint Ret=0;
    for(;Idx>0;Idx-=Idx&-Idx) Ret+=Bit[Idx];
    return Ret;
}
void Upd(int Idx){for(;Idx<=N+5;Idx+=Idx&-Idx) Bit[Idx]++;}
bool Cmp(Q A,Q B){return A.X<B.X;}
bool Cmp2(Smth A,Smth B){return A.Val<B.Val;}

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	T=1;
//	cin>>T;
	rep(t,1,T){
        cin>>N;
        for(int i=1;i<=N;++i) cin>>H[i];
        for(int i=2;i<=N-1;++i){
            Query[2*i-1].L=1;
            Query[2*i-1].R=i-1;
            Query[2*i-1].Idx=2*i-1;
            Query[2*i-1].X=H[i];
            Query[2*i].L=i+1;
            Query[2*i].R=N;
            Query[2*i].Idx=2*i;
            Query[2*i].X=H[i];
        }
        for(int i=1;i<=N;++i){
            Arr[i].Idx=i;
            Arr[i].Val=H[i];
        }
        sort(Arr+1,Arr+N+1,Cmp2);
        sort(Query+3,Query+2*N-1,Cmp);
        int Cur=1;
        for(int i=3;i<=2*N-2;++i){
            for(;Arr[Cur].Val<Query[i].X&&Cur<=N;Cur++) Upd(Arr[Cur].Idx);
            Jwb[Query[i].Idx]=Sum(Query[i].R)-Sum(Query[i].L-1);
        }
        for(int i=2;i<=N-1;++i) Ans+=(lint)Jwb[2*i-1]*Jwb[2*i];
        cout<<Ans<<endl;
	}
	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