結果

問題 No.2588 Increasing Record
ユーザー 👑 Nachia
提出日時 2023-12-23 15:18:10
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 96 ms / 3,000 ms
コード長 23,327 bytes
コンパイル時間 1,658 ms
コンパイル使用メモリ 111,516 KB
最終ジャッジ日時 2025-02-18 13:49:04
ジャッジサーバーID
（参考情報） 		judge4 / judge1
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 * 44
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#define NDEBUG
#include <atcoder/modint>
#include <atcoder/fenwicktree>
#include <vector>
#include <iterator>
#include <algorithm>
#include <functional>
#include <utility>
#include <string>
template<class Elem> struct vec;
template<class Iter>
struct seq_view{
    using Ref = typename std::iterator_traits<Iter>::reference;
    using Elem = typename std::iterator_traits<Iter>::value_type;
    Iter a, b;
    Iter begin() const { return a; }
    Iter end() const { return b; }
    int size() const { return (int)(b-a); }
    seq_view(Iter first, Iter last) : a(first), b(last) {}
    seq_view sort() const { std::sort(a, b); return *this; }
    Ref& operator[](int x){ return *(a+x); }
    template<class F = std::less<Elem>, class ret = vec<int>> ret sorti(F f = F()) const {
        ret x(size()); for(int i=0; i<size(); i++) x[i] = i;
        x().sort([&](int l, int r){ return f(a[l],a[r]); });
        return x;
    }
    template<class ret = vec<Elem>> ret col() const { return ret(begin(), end()); }
    template<class F = std::equal_to<Elem>, class ret = vec<std::pair<Elem, int>>>
    ret rle(F eq = F()) const {
        auto x = ret();
        for(auto& a : (*this)){
            if(x.size() == 0 || !eq(x[x.size()-1].first, a)) x.emp(a, 1); else x[x.size()-1].second++;
        } return x;
    }
    template<class F> seq_view sort(F f) const { std::sort(a, b, f); return *this; }
    Iter uni() const { return std::unique(a, b); }
    Iter lb(const Elem& x) const { return std::lower_bound(a, b, x); }
    Iter ub(const Elem& x) const { return std::upper_bound(a, b, x); }
    int lbi(const Elem& x) const { return lb(x) - a; }
    int ubi(const Elem& x) const { return ub(x) - a; }
    seq_view bound(const Elem& l, const Elem& r) const { return { lb(l), lb(r) }; }
    template<class F> Iter lb(const Elem& x, F f) const { return std::lower_bound(a, b, x, f); }
    template<class F> Iter ub(const Elem& x, F f) const { return std::upper_bound(a, b, x, f); }
    template<class F> Iter when_true_to_false(F f) const {
        if(a == b) return a;
        return std::lower_bound(a, b, *a,
            [&](const Elem& x, const Elem&){ return f(x); });
    }
    seq_view same(Elem x) const { return { lb(x), ub(x) }; }
    template<class F> auto map(F f) const {
        vec<typename Iter::value_type> r;
        for(auto& x : *this) r.emp(f(x));
        return r;
    }
    Iter max() const { return std::max_element(a, b); }
    Iter min() const { return std::min_element(a, b); }
    template<class F = std::less<Elem>>
    Iter min(F f) const { return std::min_element(a, b, f); }
    seq_view rev() const { std::reverse(a, b); return *this; }
};
template<class Elem>
struct vec {
    using Base = typename std::vector<Elem>;
    using Iter = typename Base::iterator;
    using CIter = typename Base::const_iterator;
    using View = seq_view<Iter>;
    using CView = seq_view<CIter>;
    vec(){}
    explicit vec(int n, const Elem& value = Elem()) : a(0<n?n:0, value) {}
    template <class I2> vec(I2 first, I2 last) : a(first, last) {}
    vec(std::initializer_list<Elem> il) : a(std::move(il)) {}
    vec(Base b) : a(std::move(b)) {}
    operator Base() const { return a; }
    Iter begin(){ return a.begin(); }
    CIter begin() const { return a.begin(); }
    Iter end(){ return a.end(); }
    CIter end() const { return a.end(); }
    int size() const { return a.size(); }
    bool empty() const { return a.empty(); }
    Elem& back(){ return a.back(); }
    const Elem& back() const { return a.back(); }
    vec sortunied(){ vec x = *this; x().sort(); x.a.erase(x().uni(), x.end()); return x; }
    Iter operator()(int x){ return a.begin() + x; }
    CIter operator()(int x) const { return a.begin() + x; }
    View operator()(int l, int r){ return { (*this)(l), (*this)(r) }; }
    CView operator()(int l, int r) const { return { (*this)(l), (*this)(r) }; }
    View operator()(){ return (*this)(0,size()); }
    CView operator()() const { return (*this)(0,size()); }
    Elem& operator[](int x){ return a[x]; }
    const Elem& operator[](int x) const { return a[x]; }
    Base& operator*(){ return a; }
    const Base& operator*() const { return a; }
    vec& push(Elem args){
        a.push_back(std::move(args));
        return *this;
    }
    template<class... Args>
    vec& emp(Args &&... args){
        a.emplace_back(std::forward<Args>(args) ...);
        return *this;
    }
    template<class Range>
    vec& app(Range& x){ for(auto& v : a) emp(v); }
    Elem pop(){
        Elem x = std::move(a.back());
        a.pop_back(); return x;
    }
    bool operator==(const vec& r) const { return a == r.a; }
    bool operator!=(const vec& r) const { return a != r.a; }
    bool operator<(const vec& r) const { return a < r.a; }
    bool operator<=(const vec& r) const { return a <= r.a; }
    bool operator>(const vec& r) const { return a > r.a; }
    bool operator>=(const vec& r) const { return a >= r.a; }
    vec<vec<Elem>> pile(int n) const { return vec<vec<Elem>>(n, *this); }
    template<class F> vec& filter(F f){
        int p = 0;
        for(int q=0; q<size(); q++) if(f(a[q])) std::swap(a[p++],a[q]);
        a.resize(p); return *this;
    }
private: Base a;
};
template<class IStr, class U, class T>
IStr& operator>>(IStr& is, vec<std::pair<U,T>>& v){ for(auto& x:v){ is >> x.first >> x.second; } return is; }
template<class IStr, class T>
IStr& operator>>(IStr& is, vec<T>& v){ for(auto& x:v){ is >> x; } return is; }
template<class OStr, class T>
OStr& operator<<(OStr& os, const vec<T>& v){
    for(int i=0; i<v.size(); i++){
        if(i){ os << ' '; } os << v[i];
    } return os;
}
#include <cassert>
namespace nachia{
template<class Elem>
class CsrArray{
public:
    struct ListRange{
        using iterator = typename std::vector<Elem>::iterator;
        iterator begi, endi;
        iterator begin() const { return begi; }
        iterator end() const { return endi; }
        int size() const { return (int)std::distance(begi, endi); }
        Elem& operator[](int i) const { return begi[i]; }
    };
    struct ConstListRange{
        using iterator = typename std::vector<Elem>::const_iterator;
        iterator begi, endi;
        iterator begin() const { return begi; }
        iterator end() const { return endi; }
        int size() const { return (int)std::distance(begi, endi); }
        const Elem& operator[](int i) const { return begi[i]; }
    };
private:
    int m_n;
    std::vector<Elem> m_list;
    std::vector<int> m_pos;
public:
    CsrArray() : m_n(0), m_list(), m_pos() {}
    static CsrArray Construct(int n, std::vector<std::pair<int, Elem>> items){
        CsrArray res;
        res.m_n = n;
        std::vector<int> buf(n+1, 0);
        for(auto& [u,v] : items){ ++buf[u]; }
        for(int i=1; i<=n; i++) buf[i] += buf[i-1];
        res.m_list.resize(buf[n]);
        for(int i=(int)items.size()-1; i>=0; i--){
            res.m_list[--buf[items[i].first]] = std::move(items[i].second);
        }
        res.m_pos = std::move(buf);
        return res;
    }
    static CsrArray FromRaw(std::vector<Elem> list, std::vector<int> pos){
        CsrArray res;
        res.m_n = pos.size() - 1;
        res.m_list = std::move(list);
        res.m_pos = std::move(pos);
        return res;
    }
    ListRange operator[](int u) { return ListRange{ m_list.begin() + m_pos[u], m_list.begin() + m_pos[u+1] }; }
    ConstListRange operator[](int u) const { return ConstListRange{ m_list.begin() + m_pos[u], m_list.begin() + m_pos[u+1] }; }
    int size() const { return m_n; }
    int fullSize() const { return (int)m_list.size(); }
};
} // namespace nachia
namespace nachia{
struct Graph {
public:
    struct Edge{
        int from, to;
        void reverse(){ std::swap(from, to); }
    };
    Graph(int n = 0, bool undirected = false, int m = 0) : m_n(n), m_e(m), m_isUndir(undirected) {}
    Graph(int n, const std::vector<std::pair<int, int>>& edges, bool undirected = false) : m_n(n), m_isUndir(undirected){
        m_e.resize(edges.size());
        for(std::size_t i=0; i<edges.size(); i++) m_e[i] = { edges[i].first, edges[i].second };
    }
    template<class Cin>
    static Graph Input(Cin& cin, int n, bool undirected, int m, bool offset = 0){
        Graph res(n, undirected, m);
        for(int i=0; i<m; i++){
            int u, v; cin >> u >> v;
            res[i].from = u - offset;
            res[i].to = v - offset;
        }
        return res;
    }
    int numVertices() const noexcept { return m_n; }
    int numEdges() const noexcept { return int(m_e.size()); }
    int addNode() noexcept { return m_n++; }
    int addEdge(int from, int to){ m_e.push_back({ from, to }); return numEdges() - 1; }
    Edge& operator[](int ei) noexcept { return m_e[ei]; }
    const Edge& operator[](int ei) const noexcept { return m_e[ei]; }
    Edge& at(int ei) { return m_e.at(ei); }
    const Edge& at(int ei) const { return m_e.at(ei); }
    auto begin(){ return m_e.begin(); }
    auto end(){ return m_e.end(); }
    auto begin() const { return m_e.begin(); }
    auto end() const { return m_e.end(); }
    bool isUndirected() const noexcept { return m_isUndir; }
    void reverseEdges() noexcept { for(auto& e : m_e) e.reverse(); }
    void contract(int newV, const std::vector<int>& mapping){
        assert(numVertices() == int(mapping.size()));
        for(int i=0; i<numVertices(); i++) assert(0 <= mapping[i] && mapping[i] < newV);
        for(auto& e : m_e){ e.from = mapping[e.from]; e.to = mapping[e.to]; }
        m_n = newV;
    }
    std::vector<Graph> induce(int num, const std::vector<int>& mapping) const {
        int n = numVertices();
        assert(n == int(mapping.size()));
        for(int i=0; i<n; i++) assert(-1 <= mapping[i] && mapping[i] < num);
        std::vector<int> indexV(n), newV(num);
        for(int i=0; i<n; i++) if(mapping[i] >= 0) indexV[i] = newV[mapping[i]]++;
        std::vector<Graph> res; res.reserve(num);
        for(int i=0; i<num; i++) res.emplace_back(newV[i], isUndirected());
        for(auto e : m_e) if(mapping[e.from] == mapping[e.to] && mapping[e.to] >= 0) res[mapping[e.to]].addEdge(indexV[e.from], indexV[e.to]);
        return res;
    }
    CsrArray<int> getEdgeIndexArray(bool undirected) const {
        std::vector<std::pair<int, int>> src;
        src.reserve(numEdges() * (undirected ? 2 : 1));
        for(int i=0; i<numEdges(); i++){
            auto e = operator[](i);
            src.emplace_back(e.from, i);
            if(undirected) src.emplace_back(e.to, i);
        }
        return CsrArray<int>::Construct(numVertices(), src);
    }
    CsrArray<int> getEdgeIndexArray() const { return getEdgeIndexArray(isUndirected()); }
    CsrArray<int> getAdjacencyArray(bool undirected) const {
        std::vector<std::pair<int, int>> src;
        src.reserve(numEdges() * (undirected ? 2 : 1));
        for(auto e : m_e){
            src.emplace_back(e.from, e.to);
            if(undirected) src.emplace_back(e.to, e.from);
        }
        return CsrArray<int>::Construct(numVertices(), src);
    }
    CsrArray<int> getAdjacencyArray() const { return getAdjacencyArray(isUndirected()); }
private:
    int m_n;
    std::vector<Edge> m_e;
    bool m_isUndir;
};
} // namespace nachia
namespace nachia {
struct Dsu{
private:
    int N;
    std::vector<int> P;
    std::vector<int> H;
public:
    Dsu() : N(0) {}
    Dsu(int n) : N(n), P(n, -1), H(n) {
        for(int i=0; i<n; i++) H[i] = i;
    }
    int leader(int u){
        if(P[u] < 0) return u;
        int v = P[u];
        while(P[v] >= 0){ P[u] = P[v]; u = v; v = P[v]; }
        return P[u];
    }
    int append(){
        int n = P.size();
        P.push_back(-1);
        H.push_back(n);
        return n;
    }
    int label(int u){ return H[leader(u)]; }
    int operator[](int u){ return H[leader(u)]; }
    void merge(int u, int v, int newLabel){
        if(newLabel < 0) newLabel = u;
        u = leader(u);
        v = leader(v);
        if(u == v){ H[u] = newLabel; return; }
        N--;
        if(-P[u] < -P[v]) std::swap(u, v);
        P[u] += P[v];
        H[P[v] = u] = newLabel;
    }
    int merge(int u, int v){ merge(u, v, u); return u; }
    int count(){ return N; }
    int size(int u){ return -P[leader(u)]; }
    bool same(int u, int v){ return leader(u) == leader(v); }
};
} // namespace nachia
namespace nachia{
struct HeavyLightDecomposition{
private:
    int N;
    std::vector<int> P;
    std::vector<int> PP;
    std::vector<int> PD;
    std::vector<int> D;
    std::vector<int> I;
    std::vector<int> rangeL;
    std::vector<int> rangeR;
public:
    HeavyLightDecomposition(const CsrArray<int>& E = CsrArray<int>::Construct(1, {}), int root = 0){
        N = E.size();
        P.assign(N, -1);
        I = {root};
        I.reserve(N);
        for(int i=0; i<(int)I.size(); i++){
            int p = I[i];
            for(int e : E[p]) if(P[p] != e){
                I.push_back(e);
                P[e] = p;
            }
        }
        std::vector<int> Z(N, 1);
        std::vector<int> nx(N, -1);
        PP.resize(N);
        for(int i=0; i<N; i++) PP[i] = i;
        for(int i=N-1; i>=1; i--){
            int p = I[i];
            Z[P[p]] += Z[p];
            if(nx[P[p]] == -1) nx[P[p]] = p;
            if(Z[nx[P[p]]] < Z[p]) nx[P[p]] = p;
        }
        for(int p : I) if(nx[p] != -1) PP[nx[p]] = p;
        PD.assign(N,N);
        PD[root] = 0;
        D.assign(N,0);
        for(int p : I) if(p != root){
            PP[p] = PP[PP[p]];
            PD[p] = std::min(PD[PP[p]], PD[P[p]]+1);
            D[p] = D[P[p]]+1;
        }
        
        rangeL.assign(N,0);
        rangeR.assign(N,0);
        
        for(int p : I){
            rangeR[p] = rangeL[p] + Z[p];
            int ir = rangeR[p];
            for(int e : E[p]) if(P[p] != e) if(e != nx[p]){
                rangeL[e] = (ir -= Z[e]);
            }
            if(nx[p] != -1){
                rangeL[nx[p]] = rangeL[p] + 1;
            }
        }
        I.resize(N);
        for(int i=0; i<N; i++) I[rangeL[i]] = i;
    }
    
    HeavyLightDecomposition(const Graph& tree, int root = 0)
        : HeavyLightDecomposition(tree.getAdjacencyArray(true), root) {}
    int numVertices() const { return N; }
    int depth(int p) const { return D[p]; }
    int toSeq(int vtx) const { return rangeL[vtx]; }
    int toVtx(int seqidx) const { return I[seqidx]; }
    int toSeq2In(int vtx) const { return rangeL[vtx] * 2 - D[vtx]; }
    int toSeq2Out(int vtx) const { return rangeR[vtx] * 2 - D[vtx] - 1; }
    int parentOf(int v) const { return P[v]; }
    int heavyRootOf(int v) const { return PP[v]; }
    int heavyChildOf(int v) const {
        if(toSeq(v) == N-1) return -1;
        int cand = toVtx(toSeq(v) + 1);
        if(PP[v] == PP[cand]) return cand;
        return -1;
    }
    int lca(int u, int v) const {
        if(PD[u] < PD[v]) std::swap(u, v);
        while(PD[u] > PD[v]) u = P[PP[u]];
        while(PP[u] != PP[v]){ u = P[PP[u]]; v = P[PP[v]]; }
        return (D[u] > D[v]) ? v : u;
    }
    int dist(int u, int v) const {
        return depth(u) + depth(v) - depth(lca(u,v)) * 2;
    }
    struct Range{
        int l; int r;
        int size() const { return r-l; }
        bool includes(int x) const { return l <= x && x < r; }
    };
    std::vector<Range> path(int r, int c, bool include_root = true, bool reverse_path = false) const {
        if(PD[c] < PD[r]) return {};
        std::vector<Range> res(PD[c]-PD[r]+1);
        for(int i=0; i<(int)res.size()-1; i++){
            res[i] = { rangeL[PP[c]], rangeL[c]+1 };
            c = P[PP[c]];
        }
        if(PP[r] != PP[c] || D[r] > D[c]) return {};
        res.back() = { rangeL[r]+(include_root?0:1), rangeL[c]+1 };
        if(res.back().l == res.back().r) res.pop_back();
        if(!reverse_path) std::reverse(res.begin(),res.end());
        else for(auto& a : res) a = { N - a.r, N - a.l };
        return res;
    }
    Range subtree(int p){ return { rangeL[p], rangeR[p] }; }
    int median(int x, int y, int z) const {
        return lca(x,y) ^ lca(y,z) ^ lca(x,z);
    }
    int la(int from, int to, int d) const {
        if(d < 0) return -1;
        int g = lca(from,to);
        int dist0 = D[from] - D[g] * 2 + D[to];
        if(dist0 < d) return -1;
        int p = from;
        if(D[from] - D[g] < d){ p = to; d = dist0 - d; }
        while(D[p] - D[PP[p]] < d){
            d -= D[p] - D[PP[p]] + 1;
            p = P[PP[p]];
        }
        return I[rangeL[p] - d];
    }
};
} // namespace nachia
#include <cstdio>
#include <cctype>
#include <cstdint>
namespace nachia{
struct CInStream{
private:
    static const unsigned int INPUT_BUF_SIZE = 1 << 17;
    unsigned int p = INPUT_BUF_SIZE;
    static char Q[INPUT_BUF_SIZE];
public:
    using MyType = CInStream;
    char seekChar(){
        if(p == INPUT_BUF_SIZE){
            size_t len = fread(Q, 1, INPUT_BUF_SIZE, stdin);
            if(len != INPUT_BUF_SIZE) Q[len] = '\0';
            p = 0;
        }
        return Q[p];
    }
    void skipSpace(){ while(isspace(seekChar())) p++; }
private:
    template<class T, int sp = 1>
    T nextUInt(){
        if constexpr (sp) skipSpace();
        T buf = 0;
        while(true){
            char tmp = seekChar();
            if('9' < tmp || tmp < '0') break;
            buf = buf * 10 + (tmp - '0');
            p++;
        }
        return buf;
    }
public:
    uint32_t nextU32(){ return nextUInt<uint32_t>(); }
    int32_t nextI32(){
        skipSpace();
        if(seekChar() == '-'){
            p++; return (int32_t)(-nextUInt<uint32_t, 0>());
        }
        return (int32_t)nextUInt<uint32_t, 0>();
    }
    uint64_t nextU64(){ return nextUInt<uint64_t>();}
    int64_t nextI64(){
        skipSpace();
        if(seekChar() == '-'){
            p++; return (int64_t)(-nextUInt<int64_t, 0>());
        }
        return (int64_t)nextUInt<int64_t, 0>();
    }
    template<class T>
    T nextInt(){
        skipSpace();
        if(seekChar() == '-'){
            p++;
            return - nextUInt<T, 0>();
        }
        return nextUInt<T, 0>();
    }
    char nextChar(){ skipSpace(); char buf = seekChar(); p++; return buf; }
    std::string nextToken(){
        skipSpace();
        std::string buf;
        while(true){
            char ch = seekChar();
            if(isspace(ch) || ch == '\0') break;
            buf.push_back(ch);
            p++;
        }
        return buf;
    }
    MyType& operator>>(unsigned int& dest){ dest = nextU32(); return *this; }
    MyType& operator>>(int& dest){ dest = nextI32(); return *this; }
    MyType& operator>>(unsigned long& dest){ dest = nextU64(); return *this; }
    MyType& operator>>(long& dest){ dest = nextI64(); return *this; }
    MyType& operator>>(unsigned long long& dest){ dest = nextU64(); return *this; }
    MyType& operator>>(long long& dest){ dest = nextI64(); return *this; }
    MyType& operator>>(std::string& dest){ dest = nextToken(); return *this; }
    MyType& operator>>(char& dest){ dest = nextChar(); return *this; }
} cin;
struct FastOutputTable{
    char LZ[1000][4] = {};
    char NLZ[1000][4] = {};
    constexpr FastOutputTable(){
        using u32 = uint_fast32_t;
        for(u32 d=0; d<1000; d++){
            LZ[d][0] = ('0' + d / 100 % 10);
            LZ[d][1] = ('0' + d /  10 % 10);
            LZ[d][2] = ('0' + d /   1 % 10);
            LZ[d][3] = '\0';
        }
        for(u32 d=0; d<1000; d++){
            u32 i = 0;
            if(d >= 100) NLZ[d][i++] = ('0' + d / 100 % 10);
            if(d >=  10) NLZ[d][i++] = ('0' + d /  10 % 10);
            if(d >=   1) NLZ[d][i++] = ('0' + d /   1 % 10);
            NLZ[d][i++] = '\0';
        }
    }
};
struct COutStream{
private:
    using u32 = uint32_t;
    using u64 = uint64_t;
    using MyType = COutStream;
    static const u32 OUTPUT_BUF_SIZE = 1 << 17;
    static char Q[OUTPUT_BUF_SIZE];
    static constexpr FastOutputTable TB = FastOutputTable();
    u32 p = 0;
    static constexpr u32 P10(u32 d){ return d ? P10(d-1)*10 : 1; }
    static constexpr u64 P10L(u32 d){ return d ? P10L(d-1)*10 : 1; }
    template<class T, class U> static void Fil(T& m, U& l, U x){ m = l/x; l -= m*x; }
    void next_dig9(u32 x){
        u32 y;
        Fil(y, x, P10(6));
        nextCstr(TB.LZ[y]);
        Fil(y, x, P10(3));
        nextCstr(TB.LZ[y]); nextCstr(TB.LZ[x]);
    }
public:
    void nextChar(char c){
        Q[p++] = c;
        if(p == OUTPUT_BUF_SIZE){ fwrite(Q, p, 1, stdout); p = 0; }
    }
    void nextEoln(){ nextChar('\n'); }
    void nextCstr(const char* s){ while(*s) nextChar(*(s++)); }
    void nextU32(uint32_t x){
        u32 y = 0;
        if(x >= P10(9)){
            Fil(y, x, P10(9));
            nextCstr(TB.NLZ[y]); next_dig9(x);
        }
        else if(x >= P10(6)){
            Fil(y, x, P10(6));
            nextCstr(TB.NLZ[y]);
            Fil(y, x, P10(3));
            nextCstr(TB.LZ[y]); nextCstr(TB.LZ[x]);
        }
        else if(x >= P10(3)){
            Fil(y, x, P10(3));
            nextCstr(TB.NLZ[y]); nextCstr(TB.LZ[x]);
        }
        else if(x >= 1) nextCstr(TB.NLZ[x]);
        else nextChar('0');
    }
    void nextI32(int32_t x){
        if(x >= 0) nextU32(x);
        else{ nextChar('-'); nextU32((u32)-x); }
    }
    void nextU64(uint64_t x){
        u32 y = 0;
        if(x >= P10L(18)){
            Fil(y, x, P10L(18));
            nextU32(y);
            Fil(y, x, P10L(9));
            next_dig9(y); next_dig9(x);
        }
        else if(x >= P10L(9)){
            Fil(y, x, P10L(9));
            nextU32(y); next_dig9(x);
        }
        else nextU32(x);
    }
    void nextI64(int64_t x){
        if(x >= 0) nextU64(x);
        else{ nextChar('-'); nextU64((u64)-x); }
    }
    template<class T>
    void nextInt(T x){
        if(x < 0){ nextChar('-'); x = -x; }
        if(!(0 < x)){ nextChar('0'); return; }
        std::string buf;
        while(0 < x){
            buf.push_back('0' + (int)(x % 10));
            x /= 10;
        }
        for(int i=(int)buf.size()-1; i>=0; i--){
            nextChar(buf[i]);
        }
    }
    void writeToFile(bool flush = false){
        fwrite(Q, p, 1, stdout);
        if(flush) fflush(stdout);
        p = 0;
    }
    COutStream(){ Q[0] = 0; }
    ~COutStream(){ writeToFile(); }
    MyType& operator<<(unsigned int tg){ nextU32(tg); return *this; }
    MyType& operator<<(unsigned long tg){ nextU64(tg); return *this; }
    MyType& operator<<(unsigned long long tg){ nextU64(tg); return *this; }
    MyType& operator<<(int tg){ nextI32(tg); return *this; }
    MyType& operator<<(long tg){ nextI64(tg); return *this; }
    MyType& operator<<(long long tg){ nextI64(tg); return *this; }
    MyType& operator<<(const std::string& tg){ nextCstr(tg.c_str()); return *this; }
    MyType& operator<<(const char* tg){ nextCstr(tg); return *this; }
    MyType& operator<<(char tg){ nextChar(tg); return *this; }
} cout;
char CInStream::Q[INPUT_BUF_SIZE];
char COutStream::Q[OUTPUT_BUF_SIZE];
} // namespace nachia
#define rep(i,n) for(int i=0; i<(int)(n); i++)
int main(){
    using namespace std;
    using Modint = atcoder::static_modint<998244353>;
    using nachia::cin;
    using nachia::cout;
    int N, M; cin >> N >> M;
    auto graph = nachia::Graph::Input(cin, N, false, M, 1);
    auto mtree = nachia::Graph(N, false);
    auto dsu = nachia::Dsu(N);
    graph.reverseEdges();
    auto adj = graph.getAdjacencyArray();
    rep(u,N) for(int v : adj[u]) if(!dsu.same(u, v)){
        mtree.addEdge(u, dsu[v]);
        dsu.merge(u, v, u);
    }
    auto hld = nachia::HeavyLightDecomposition(mtree, N-1);
    auto ds = atcoder::fenwick_tree<Modint>(N+1);
    auto rangeAdd = [&](int l, int r, Modint val){ ds.add(l, val); ds.add(r, -val); };
    auto pointGet = [&](int p) -> Modint { return ds.sum(0, p+1); };
    Modint ans = 0;
    rep(v,N){
        sort(adj[v].begin(), adj[v].end(), [&](int a, int b){ return hld.toSeq(a) < hld.toSeq(b); });
        Modint f = 1;
        for(int u : adj[v]) f += pointGet(hld.toSeq(u));
        rep(i,adj[v].size()-1) f -= pointGet(hld.toSeq(hld.lca(adj[v][i], adj[v][i+1])));
        auto [l,r] = hld.subtree(v);
        rangeAdd(l, r, f);
        ans += f;
    }
    cout << ans.val() << '\n';
    return 0;
}
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