結果

問題 No.992 最長増加部分列の数え上げ
ユーザー mugen_1337
提出日時 2021-03-31 15:51:40
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 513 ms / 2,000 ms
コード長 8,395 bytes
コンパイル時間 3,851 ms
コンパイル使用メモリ 220,108 KB
最終ジャッジ日時 2025-01-20 01:59:36
ジャッジサーバーID
（参考情報） 		judge1 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 42
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ソースコード

diff #
プレゼンテーションモードにする

#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}
struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}
template<typename T>
int LongestIncreasingSubsequence(vector<T> v,bool strict=true){
    vector<T> lis;
    for(auto &x:v){
        typename vector<T>::iterator ite;
        if(strict) ite=lower_bound(begin(lis),end(lis),x);
        else       ite=upper_bound(begin(lis),end(lis),x);
        if(ite==end(lis)) lis.push_back(x);
        else              *ite=x;
    }
    return int(lis.size());
}
template<ll Mod>
struct ModInt{
    long long x;
    ModInt():x(0){}
    ModInt(long long y):x(y>=0?y%Mod:(Mod-(-y)%Mod)%Mod){}
    ModInt &operator+=(const ModInt &p){
        if((x+=p.x)>=Mod) x-=Mod;
        return *this;
    }
    ModInt &operator-=(const ModInt &p){
        if((x+=Mod-p.x)>=Mod)x-=Mod;
        return *this;
    }
    ModInt &operator*=(const ModInt &p){
        x=(int)(1ll*x*p.x%Mod);
        return *this;
    }
    ModInt &operator/=(const ModInt &p){
        (*this)*=p.inverse();
        return *this;
    }
    ModInt operator-()const{return ModInt(-x);}
    ModInt operator+(const ModInt &p)const{return ModInt(*this)+=p;}
    ModInt operator-(const ModInt &p)const{return ModInt(*this)-=p;}
    ModInt operator*(const ModInt &p)const{return ModInt(*this)*=p;}
    ModInt operator/(const ModInt &p)const{return ModInt(*this)/=p;}
    bool operator==(const ModInt &p)const{return x==p.x;}
    bool operator!=(const ModInt &p)const{return x!=p.x;}
    ModInt inverse()const{
        int a=x,b=Mod,u=1,v=0,t;
        while(b>0){
            t=a/b;
            swap(a-=t*b,b);swap(u-=t*v,v);
        }
        return ModInt(u);
    }
    ModInt pow(long long n)const{
        ModInt ret(1),mul(x);
        while(n>0){
            if(n&1) ret*=mul;
            mul*=mul;n>>=1;
        }
        return ret;
    }
    friend ostream &operator<<(ostream &os,const ModInt &p){return os<<p.x;}
    friend istream &operator>>(istream &is,ModInt &a){long long t;is>>t;a=ModInt<Mod>(t);return (is);}
    static int get_mod(){return Mod;}
};
using mint=ModInt<1000000007>;
template<typename BitType,int MAXLOG,typename Monoid>
struct BinaryTrieMonoid{
    private:
    struct Node{
        Node *nxt[2];
        Monoid val;
        Node(Monoid val):nxt{nullptr,nullptr},val(val){}
    };
    Node *root;
    using F=function<Monoid(Monoid,Monoid)>;
    F f;
    const Monoid e;
    Monoid query(BitType a,BitType b,Node *cur,BitType l,BitType r,int dep,BitType xor_val){
        if(a<=l and r<=b) return (cur?cur->val:e);
        if(dep<0 or b<=l or r<=a or !cur) return e;
        bool x0=(xor_val>>dep)&1;
        Monoid L=query(a,b,cur->nxt[x0],l,(l+r)/2,dep-1,xor_val);
        Monoid R=query(a,b,cur->nxt[x0^1],(l+r)/2,r,dep-1,xor_val);
        return f(L,R);
    }
    void update(Node *cur,Monoid x,BitType bit,int dep){
        if(dep==-1){
            cur->val=x;
            return ;
        }
        bool go_to=(bit>>dep)&1;
        if(!cur->nxt[go_to]) cur->nxt[go_to]=new Node(e);
        update(cur->nxt[go_to],x,bit,dep-1);
        cur->val=f(cur->nxt[0]?cur->nxt[0]->val:e,cur->nxt[1]?cur->nxt[1]->val:e);
        return ;
    }
    public:
    BinaryTrieMonoid(F f,const Monoid &e):root(new Node(e)),f(f),e(e){}
    // fold [l,r)
    // xor_valを指定したとき，可換じゃない演算だと壊れると思います．多分
    Monoid query(BitType l,BitType r,BitType xor_val=0){
        return query(l,r,root,0,BitType(1)<<MAXLOG,MAXLOG-1,xor_val);
    }
    void update(BitType bit,Monoid x){
        update(root,x,bit,MAXLOG-1);
    }
    Monoid operator[](const BitType &k){
        return query(k,k+1);
    }
};
template<typename Monoid>
struct SegmentTree{
    using F=function<Monoid(Monoid,Monoid)>;
    private:
    int sz;
    vector<Monoid> seg;
    Monoid query(int a,int b,int k,int l,int r){
        if(a<=l and r<=b)   return seg[k];
        if(b<=l or r<=a)    return M0;
        Monoid L=query(a,b,2*k,l,(l+r)/2);
        Monoid R=query(a,b,2*k+1,(l+r)/2,r);
        return f(L,R);
    }
    template<typename C>
    int find_first(int a,const C &check,Monoid &acc,int k,int l,int r){
        if(k>=sz){
            acc=f(acc,seg[k]);
            if(check(acc))  return -1;
            else            return k-sz;
        }
        int m=(l+r)/2;
        if(m<=a) return find_first(a,check,acc,2*k+1,m,r);
        if(a<=l and check(f(acc,seg[k]))){
            acc=f(acc,seg[k]);
            return -1;
        }
        int x=find_first(a,check,acc,2*k+0,l,m);
        if(x>=0) return x;
        return find_first(a,check,acc,2*k+1,m,r);
    }
    template<typename C>
    int find_last(int b,const C &check,Monoid &acc,int k,int l,int r){
        if(k>=sz){
            acc=f(acc,seg[k]);
            if(check(acc))  return -1;
            else            return k-sz+1;//ここはfalse, +1した位置はtrue
        }
        int m=(l+r)/2;
        if(b<=m) return find_last(b,check,acc,2*k,l,m);
        if(r<=b and check(f(acc,seg[k]))){
            acc=f(acc,seg[k]);
            return -1;
        }
        int x=find_last(b,check,acc,2*k+1,m,r);
        if(x>=0) return x;
        return find_last(b,check,acc,2*k,l,m);
    }
    public:
    F f;
    Monoid M0;// モノイドの元
    SegmentTree(int n,F f,Monoid M0):f(f),M0(M0){
        sz=1;
        while(sz<n)sz<<=1;
        seg.assign(2*sz,M0);
    }
    void set(int k,Monoid x){
        seg[k+sz]=x;
    }
    void build(){
        for(int k=sz-1;k>0;k--) seg[k]=f(seg[2*k],seg[2*k+1]);
    }
    void update(int k,Monoid x){
        k+=sz;
        seg[k]=x;
        k>>=1;
        for(;k;k>>=1) seg[k]=f(seg[2*k],seg[2*k+1]);
    }
    Monoid query(int a,int b){
        return query(a,b,1,0,sz);
    }
    // http://codeforces.com/contest/914/submission/107505449
    // max x, check(query(a, x)) = true 
    template<typename C>
    int find_first(int a,const C &check){
        Monoid val=M0;
        return find_first(a,check,val,1,0,sz);
    }
    // http://codeforces.com/contest/914/submission/107505582
    // min x, check(query(x, b)) = true
    template<typename C>
    int find_last(int b,C &check){
        Monoid val=M0;
        return find_last(b,check,val,1,0,sz);
    }
};
int f(int a,int b){
    return max(a,b);
}
mint g(mint a,mint b){
    return a+b;
}
signed main(){
    int n;cin>>n;
    vector<int> a(n);
    cin>>a;
    int M=LongestIncreasingSubsequence(a);
    {
        vector<int> v=a;
        sort(ALL(v));
        v.erase(unique(ALL(v)),end(v));
        for(auto &x:a) x=lower_bound(ALL(v),x)-begin(v);
    }
    
    vector<int> l(n),r(n);
    {
        SegmentTree<int> seg(n,f,0);
        rep(i,n){
            l[i]=seg.query(0,a[i])+1;
            if(seg.query(a[i],a[i]+1)<l[i]) seg.update(a[i],l[i]);
        }
    }
    {
        SegmentTree<int> seg(n,f,0);
        for(int i=n-1;i>=0;i--){
            r[i]=seg.query(a[i]+1,n)+1;
            if(seg.query(a[i],a[i]+1)<r[i]) seg.update(a[i],r[i]);
        }
    }
    vector<int> idx(n,-1);
    rep(i,n)if(l[i]+r[i]-1==M) idx[i]=l[i]-1;
    vector<BinaryTrieMonoid<int,18,mint> > segs;
    rep(i,M){
        BinaryTrieMonoid<int,18,mint> tmp(g,0);
        segs.push_back(tmp);
    }
    vector<mint> dp(n,0);
    rep(i,n){
        if(idx[i]<0) continue;
        if(idx[i]==0) dp[i]=1;
        else dp[i]=segs[idx[i]-1].query(0,a[i]);
        mint t=segs[idx[i]].query(a[i],a[i]+1);
        segs[idx[i]].update(a[i],t+dp[i]);
    }
    cout<<segs[M-1].query(0,1<<18)<<endl;
    return 0;
}
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