Submission #307115

#	Time	Username	Problem	Language	Result	Execution time	Memory
307115		Hemimor	Mountains (NOI20_mountains)	C++14	24 / 100	472 ms	14348 KiB

Mountains

#include <algorithm>
#include <iostream>
#include <iomanip>
#include <numeric>
#include <cassert>
#include <vector>
#include <random>
#include <cmath>
#include <queue>
#include <set>
#include <map>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=998244353;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

vi vin(int n,int d=0){
	vi a(n);
	for(auto &i:a){
		cin>>i;
		i-=d;
	}
	return a;
}

vl vln(int n,int d=0){
	vl a(n);
	for(auto &i:a){
		cin>>i;
		i-=d;
	}
	return a;
}

vvi gin(int n,int m,int d=1){
	vvi g(n);
	for(int i=0;i<m;i++){
		int u,v;
		cin>>u>>v;
		u-=d,v-=d;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	return g;
}

void vout(vi a){
	int n=a.size();
	cout<<n<<" :";
	for(auto i:a) cout<<' '<<i;
	cout<<endl;
}

class Segment_Tree{
	private:
	int n;
	vi date;
	public:
	Segment_Tree(int n_){
		n=1;
		while(n<n_) n*=2;
		date=vi(2*n-1);
	}
	void Update(int k,int x){
		k+=n-1;
		date[k]+=x;
		while(k>0){
			k=(k-1)/2;
			date[k]=date[k*2+1]+date[k*2+2];
		}
	}
	int Query(int a,int b){
		a+=n-1;b+=n-1;
		int m=0;
		while(a<b){
			if(a%2==0) m+=date[a++];
			if(b%2==0) m+=date[--b];
			a/=2;b/=2;
		}
		return m;
	}
	int Open(int k){return date[k+n-1];}
};

int n;
vi a;

vi f(){
	Segment_Tree st(n);
	vi b(n);
	for(int i=0;i<n;i++){
		b[i]=st.Query(0,a[i]);
		st.Update(a[i],1);
	}
	reverse(a.begin(),a.end());
	return b;
}

int main(){
	cin>>n;
	a=vin(n);
	vi b=a;
	sort(b.begin(),b.end());
	map<int,int> mp;
	for(int i=0;i<n;i++) mp[b[i]]=i;
	for(int i=0;i<n;i++) a[i]=mp[a[i]];
	b=f();
	vi c=f();
	ll res=0;
	for(int i=0;i<n;i++) res+=(ll)b[i]*c[n-i-1];
	cout<<res<<endl;
}

• Subtask 1: 2 / 2
• Subtask 2: 4 / 4
• Subtask 3: 9 / 9
• Subtask 4: 0 / 36
• Subtask 5: 0 / 28
• Subtask 6: 9 / 9
• Subtask 7: 0 / 12