// https://codeforces.com/contest/1461/problem/F #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define X first #define Y second #define pb push_back #define rep(X,Y) for (int (X) = 0;(X) < (int)(Y);++(X)) #define reps(X,S,Y) for (int (X) = (int)(S);(X) < (int)(Y);++(X)) #define rrep(X,Y) for (int (X) = (int)(Y)-1;(X) >=0;--(X)) #define rreps(X,S,Y) for (int (X) = (int)(Y)-1;(X) >= (int)(S);--(X)) #define repe(X,Y) for ((X) = 0;(X) < (Y);++(X)) #define peat(X,Y) for (;(X) < (Y);++(X)) #define all(X) (X).begin(),(X).end() #define rall(X) (X).rbegin(),(X).rend() #define eb emplace_back #define UNIQUE(X) (X).erase(unique(all(X)),(X).end()) #define Endl endl #define NL <<"\n" #define cauto const auto using namespace std; using ll=long long; using pii=pair; using pll=pair; template using vv=vector>; template inline bool MX(T &l,const T &r){return l inline bool MN(T &l,const T &r){return l>r?l=r,1:0;} //#undef NUIP #ifdef NUIP #include "benri.h" #else #define out(args...) #endif void ouT(ll x,int d=3){auto re=to_string(x);if((int)re.size()>d) re=x>0?"oo":"-oo";cout<vector table(int n, T v){ return vector(n, v);} template auto table(int n, Args... args){auto val = table(args...); return vector(n, move(val));} #endif template pair operator+(const pair &p,const pair &q){ return {p.X+q.X,p.Y+q.Y};} template pair& operator+=(pair &p,const pair &q){ p.X+=q.X; p.Y+=q.Y; return p;} template pair operator-(const pair &p,const pair &q){ return {p.X-q.X,p.Y-q.Y};} template pair& operator-=(pair &p,const pair &q){ p.X-=q.X; p.Y-=q.Y; return p;} template istream& operator>>(istream &is, pair &p){ is>>p.X>>p.Y; return is;} template T read(){ T re; cin>>re; return move(re);} template T read(const T &dec){ T re; cin>>re; return re-dec;} template vector readV(const int sz){ vector re(sz); for(auto &x:re) x=read(); return move(re);} template vector readV(const int sz, const T &dec){ vector re(sz); for(auto &x:re) x=read(dec); return move(re);} vv readG(const int &n,const int &m){ vv g(n); rep(_,m){ cauto a=read(1),b=read(1); g[a].pb(b); g[b].pb(a);} return move(g);} vv readG(const int &n){ return readG(n,n-1);} #define TT cauto TTT=read();rep(_,TTT) const ll MOD=1e9+7; //998244353; ll modpow_(ll r,ll n,ll m=MOD){ ll re=1,d=r%m; if(n<0)(n%=m-1)+=m-1; for(;n;n/=2){ if(n&1)(re*=d)%=m; (d*=d)%=m; } return re; } template struct ModInt{ int v; ModInt(int v=0):v(v){} ModInt operator+(const ModInt &n)const{return v+n.v=mod) v-=mod; return *this;} ModInt& operator-=(const ModInt &n){v-=n.v; if(v<0) v+=mod; return *this;} ModInt& operator*=(const ModInt &n){v=ll(v)*n.v%mod; return *this;} ModInt& operator/=(const ModInt &n){v=ll(v)*modpow_(n.v,-1,mod)%mod; return *this;} ModInt& operator+=(const ll &n){v+=n; if(v>=mod) v-=mod; return *this;} ModInt& operator-=(const ll &n){v-=n; if(v<0) v+=mod; return *this;} ModInt& operator*=(const ll &n){v=ll(v)*n%mod; return *this;} ModInt& operator/=(const ll &n){v=ll(v)*modpow_(n,-1,mod)%mod; return *this;} bool operator==(const ModInt &n)const{return v==n.v;}; bool operator!=(const ModInt &n)const{return v!=n.v;}; ModInt& operator++(){ return operator+=(1); } ModInt& operator--(){ return operator-=(1); } ModInt operator++(int i){ ModInt tmp(*this); operator++(); return tmp; } ModInt operator--(int i){ ModInt tmp(*this); operator--(); return tmp; } }; #ifdef NUIP class MINT_FRAC____{ public: unordered_map dict; MINT_FRAC____(int n){ rep(p,n+1)reps(q,1,n+1)if(__gcd(p,q)==1){ dict[1ll*p*modpow_(q,-1)%MOD]=pii(p,q); dict[MOD-1ll*p*modpow_(q,-1)%MOD]=pii(-p,q); } } } Il1Il1Il1(1000); template ostream& operator<<(ostream &os,const ModInt &n){if(Il1Il1Il1.dict.count(n.v)) os< ostream& operator<<(ostream &os,const ModInt &n){return os< ModInt operator+(const ll &n,const ModInt &m){return m.v+n ModInt operator-(const ll &n,const ModInt &m){return n-m.v<0 ? n-m.v+mod : n-m.v;} template ModInt operator*(const ll &n,const ModInt &m){return ll(m.v)*(n%mod)%mod;} template ModInt operator/(const ll &n,const ModInt &m){return ModInt(n%mod)/m;} typedef ModInt mint; template ModInt modpow(ModInt r,ll n){ ModInt re(1); if(n<0)(n%=mod-1)+=mod-1; for(;n;n/=2){if(n&1) re*=r; r*=r;} return re;} vector fact,finv,inv; mint comb(ll n,ll r){ if(n &re,int n){ re.resize(n+1); re[1]=1; for(int i=2;i<=n;++i)re[i]=re[MOD%i]*(MOD-MOD/i);} void Facts(vector &re,int n){ re.resize(n+1); re[0]=1; rep(i,n)re[i+1]=re[i]*(i+1);} void Factinvs(vector &re,const vector &inv,int n){ re.resize(n+1); re[0]=1; rep(i,n)re[i+1]=re[i]*inv[i+1];} public: Doralion(int n){ Modinvs(inv,n); Facts(fact,n); Factinvs(finv,inv,n);} } doralion(1123456); using pmm=pair; mint modpow(ll r,ll n){ return modpow_(r,n);} int main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout< &vs)->mint{ if(vs.empty()) return 0; if(count(all(vs),1)==vs.size()){ return (mint)vs.size(); } ll prod=1; for(cauto v:vs) MN(prod*=v,MOD); if(prod==MOD){ mint prod=1; for(cauto v:vs) prod*=v; int l=0; while(vs[l]==1) ++l, prod+=1; int r=vs.size(); while(vs[r-1]==1) --r, prod+=1;; return prod; } vector ps; vector ind; rep(i,vs.size()){ cauto v=vs[i]; if(ps.empty() || ps.back().X!=(v==1)) ps.eb(v==1,v!=1), ind.eb(i); if(v==1) ++ps.back().Y; else MN(ps.back().Y*=v,MOD); } ind.eb(vs.size()); out(ps,ind,1); cauto n=(int)ps.size(); vector dp(n+1); rep(i,n){ ll p=1; reps(j,i,n){ if(ps[j].X==0) p*=ps[j].Y; MX(dp[j+1],pll(dp[i].X+p,i)); } if(ps[i].X) MX(dp[i+1],pll(dp[i].X+ps[i].Y,n)); } out(dp,1); mint re=0; for(int i=n;i;){ cauto t=dp[i].Y; if(t==n){ --i; rep(_,ps[i].Y) re+=1; }else{ mint prod=1; rreps(j,ind[t],ind[i]) prod*=vs[j]; re+=prod; i=t; } out(i,re,1); } return re; }; cout<