ソースコード
// g++ macro.cpp -std=c++14
#include <bits/stdc++.h>
typedef long long ll;
const int INF = 1e9;
const int MOD = 1e9+7;
const ll LINF = 1e18;
using namespace std;
#define dump(x) cout << #x << " = " << (x) << endl;
#define YES(n) cout << ((n) ? "YES" : "NO" ) << endl
#define Yes(n) cout << ((n) ? "Yes" : "No" ) << endl
#define POSSIBLE(n) cout << ((n) ? "POSSIBLE" : "IMPOSSIBLE" ) << endl
#define Possible(n) cout << ((n) ? "Possible" : "Impossible" ) << endl
#define possible(n) cout << ((n) ? "possible" : "impossible" ) << endl
#define SANKOU(n,a,b) cout << ((n) ? (#a) : (#b) ) << endl
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) for(int i=0;i<(n);++i)
#define REPR(i,n) for(int i=n;i>=0;i--)
#define FOREACH(x,a) for(auto& (x) : (a) )
#define WFA(d,v) REP(k,v)REP(i,v)REP(j,v)d[i][j]=min(d[i][j],d[i][k]+d[k][j])
#define SCOUT(x) cout<<(x)<<" "
#define ENDL cout<<endl
#define VECCIN(x) for(auto&youso_: (x) )cin>>youso_
#define VECIN2(x,y) REP(i,x.size())cin>>x[i]>>y[i]
#define VECCOUT(x) if(1){for(auto tt=x.begin();tt!=x.end();tt++){if(tt!=x.begin())cout<<" ";cout<<(*tt);}cout<<endl;}
#define ALL(obj) (obj).begin(),(obj).end()
#define EXIST(n,x) (find(ALL(n),x)!=n.end())
#define UNIQUE(obj) sort(ALL( obj )); obj.erase(unique(ALL(obj)),obj.end())
#define EN(x) if(1){cout<<#x<<endl;return 0;}
#define COUT(x) cout<<(x)<<endl
void CINT(){}
template <class Head,class... Tail>
void CINT(Head&& head,Tail&&... tail){
cin>>head;
CINT(move(tail)...);
}
#define CIN(...) int __VA_ARGS__;CINT(__VA_ARGS__)
#define LCIN(...) ll __VA_ARGS__;CINT(__VA_ARGS__)
#define SCIN(...) string __VA_ARGS__;CINT(__VA_ARGS__)
template <class T = ll>
T IN(){T x;cin>>x;return (x);}
template <class Head>
void VT(Head head){}
template <class Head,class Seco,class... Tail>
void VT(Head&& head,Seco&& seco,Tail&&... tail){
seco.resize(head);
VT(head,move(tail)...);
}
void VT2(){}
template <class Head,class... Tail>
void VT2(Head&& head,Tail&&... tail){
VECCIN(head);
VT2(move(tail)...);
}
template <class Head>
void VT3(Head&& head){}
template <class Head,class Seco,class... Tail>
void VT3(Head&& head,Seco&& seco,Tail&&... tail){
seco[head]=IN();
VT3(head,move(tail)...);
}
#define VC1(n,...) V __VA_ARGS__;VT(n,__VA_ARGS__);VT2(__VA_ARGS__); //aaabbbccc
#define VC2(n,...) V __VA_ARGS__;VT(n,__VA_ARGS__);REP(i,n)VT3(i,__VA_ARGS__); //abcabcabc
// #include <boost/multiprecision/cpp_int.hpp>
// using namespace boost::multiprecision; // cpp_int
#define P pair<ll,ll>
#define V vector<ll>
#define M map<ll,ll>
#define S set<ll>
#define pb(a) push_back(a)
#define mp make_pair
ll sqMod(ll x){
return 1LL*x*x%MOD;
}
ll powMod(ll x,ll n){//xのn乗
if(n==0)return 1;
else if(n==1)return x;
if(n%2==0)return (sqMod(powMod(x,n/2)%MOD)%MOD);
else return ((x*sqMod(powMod(x,n/2)%MOD)%MOD)%MOD);
}
V kaitable,gyakutable;
ll ncr(int n,int r){
return 1LL * kaitable[n] * gyakutable[n-r] % MOD * gyakutable[r]% MOD;
}
ll nhr(int n,int r){
return ncr(n+r-1,r);
}
void calcTable(int t){
kaitable = V(t);
gyakutable = V(t);
kaitable[0]=1;
gyakutable[0]=1;
FOR(i,1,t){
kaitable[i] = 1LL * kaitable[i-1] * i % MOD;
gyakutable[i] = powMod(kaitable[i],1e9+5)%MOD;
}
}
class LazySegmentTree{//遅延セグ木 初期値0で総和を出すやつ
public:
LazySegmentTree(ll n,V v);
void addVal(ll st,ll en,ll val,ll k,ll l,ll r);
ll calcVal(ll st,ll en,ll k,ll l,ll r);//半開区間 3,6なら3,4,5の総和
void eval(ll k,ll l,ll r);
V elements,lazy;
ll pnum;
};
LazySegmentTree::LazySegmentTree(ll n,V v){
pnum=1;while(pnum<n)pnum*=2;
elements=V(pnum*2-1,0);
lazy=V(pnum*2-1,0);
REP(i,n)
elements[i+pnum-1] = v[i];
REPR(i,pnum-2)
elements[i]=elements[i*2+1]+elements[i*2+2];
}
void LazySegmentTree::addVal(ll st,ll en,ll val,ll k=0,ll l=0,ll r=-1){
if(r<0)r=pnum;
eval(k,l,r);
if(en<=l || r<=st) return ;
if(st<=l && r<=en){
lazy[k] += (r-l) * val;
eval(k,l,r);
}else{
addVal(st,en,val,2*k+1,l,(l+r)/2);
addVal(st,en,val,2*k+2,(l+r)/2,r);
elements[k]=elements[2*k+1]+elements[2*k+2];
elements[k]%=MOD;
}
}
void LazySegmentTree::eval(ll k,ll l,ll r){
if(!lazy[k])return ;
elements[k]+=lazy[k];
elements[k]%=MOD;
if(r-l>1){
lazy[2*k+1]+=lazy[k]/2;
lazy[2*k+2]+=lazy[k]/2;
}
lazy[k]=0;
}
ll LazySegmentTree::calcVal(ll st,ll en,ll k=0,ll l=0,ll r=-1) {
if(r<0)r=pnum;
eval(k,l,r);
if(en<=l || r<=st)return 0;
if(st<=l && r<=en)return elements[k];
ll vl = calcVal(st,en,2*k+1,l,(l+r)/2);
ll vr = calcVal(st,en,2*k+2,(l+r)/2,r);
return vl + vr;
}
int main(){
CIN(n);VC1(n,a);
sort(ALL(a));
LazySegmentTree lazy(n, V(n, 0));
lazy.addVal(0, 1, 1);
REP(i,n){
lazy.addVal(distance(a.begin(), upper_bound(ALL(a), a[i])), n+1, lazy.calcVal(i, i+1)%MOD);
}
ll sum = 0;
REP(i,n){
sum += lazy.calcVal(i, i+1);
sum %= MOD;
}
COUT(sum);
/*
CIN(n,k,b);VC1(n,a);
// 順列を総和にするbitDP
V dp(1<<n, LINF);
V sum(1<<n,0);
REP(i,1<<n){
REP(j,n)
if(i&(1<<j))
sum[i]+=a[j];
}
dp[0]=0;
REP(i,1<<n){
REP(j,n){
if(i&(1<<j))
continue;
int flag = 0;
if(sum[i] % b)
++flag;
if(sum[i|(1<<j)] % b && sum[i] / b != sum[i|(1<<j)] / b)
++flag;
dp[i|(1<<j)] = min(dp[i|(1<<j)], dp[i] + flag);
}
}
COUT(dp.back());
*/
return 0;
}