結果

問題 No.1712 Read and Pile
ユーザー leaf_1415
提出日時 2021-10-15 23:20:45
言語 C++11
(gcc 13.3.0)
結果
AC  
実行時間 805 ms / 2,000 ms
コード長 9,593 bytes
コンパイル時間 1,225 ms
コンパイル使用メモリ 106,468 KB
実行使用メモリ 24,340 KB
最終ジャッジ日時 2024-09-17 18:14:37
合計ジャッジ時間 19,317 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge6
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 * 40
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

#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstdlib>
#include <cassert>
#include <vector>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <string>
#include <algorithm>
#include <utility>
#include <complex>
#include <unordered_set>
#include <unordered_map>
#define rep(x, s, t) for(ll x = (s); (x) <= (t); (x)++)
#define per(x, s, t) for(ll x = (s); (x) >= (t); (x)--)
#define reps(x, s) for(ll x = 0; (x) < (ll)(s).size(); (x)++)
#define chmin(x, y) (x) = min((x), (y))
#define chmax(x, y) (x) = max((x), (y))
#define sz(x) ((ll)(x).size())
#define all(x) (x).begin(),(x).end()
#define outl(...) dump_func(__VA_ARGS__)
#define outf(x) cout << fixed << setprecision(16) << (x) << endl
#define inf 2e18
#define eps 1e-9
const double PI = 3.1415926535897932384626433;
using namespace std;
typedef long long llint;
typedef long long ll;
typedef pair<ll, ll> P;
struct edge{
    ll to, cost;
    edge(){}
    edge(ll a, ll b){ to = a, cost = b;}
};
const int dx[] = {1, 0, -1, 0}, dy[] = {0, -1, 0, 1};
//int mod = 1000000007;
int mod = 998244353;
struct mint{
    int x;
    mint(ll y = 0){if(y < 0 || y >= mod) y = (y%mod+mod)%mod; x = y;}
    mint(const mint &ope) {x = ope.x;}
    
    mint operator-(){return mint(-x);}
    mint operator+(const mint &ope){return mint(x) += ope;}
    mint operator-(const mint &ope){return mint(x) -= ope;}
    mint operator*(const mint &ope){return mint(x) *= ope;}
    mint operator/(const mint &ope){return mint(x) /= ope;}
    mint& operator+=(const mint &ope){
        x += ope.x;
        if(x >= mod) x -= mod;
        return *this;
    }
    mint& operator-=(const mint &ope){
        x += mod - ope.x;
        if(x >= mod) x -= mod;
        return *this;
    }
    mint& operator*=(const mint &ope){
        ll tmp = x;
        tmp *= ope.x, tmp %= mod;
        x = tmp;
        return *this;
    }
    mint& operator/=(const mint &ope){
        ll n = mod-2; mint mul = ope;
        while(n){
            if(n & 1) *this *= mul;
            mul *= mul;
            n >>= 1;
        }
        return *this;
    }
    mint inverse(){return mint(1) / *this;}
    bool operator ==(const mint &ope){return x == ope.x;}
    bool operator !=(const mint &ope){return x != ope.x;}
    bool operator <(const mint &ope){return x < ope.x;}
};
mint modpow(mint a, ll n){
    if(n == 0) return mint(1);
    if(n % 2) return a * modpow(a, n-1);
    else return modpow(a*a, n/2);
}
istream& operator >>(istream &is, mint &ope){
    ll t; is >> t, ope.x = t;
    return is;
}
ostream& operator <<(ostream &os, mint &ope){return os << ope.x;}
ostream& operator <<(ostream &os, const mint &ope){return os << ope.x;}
vector<mint> fact, fact_inv;
void make_fact(int n){
    fact.resize(n+1), fact_inv.resize(n+1);
    fact[0] = mint(1); rep(i, 1, n) fact[i] = fact[i-1] * mint(i);
    fact_inv[n] = fact[n].inverse(); per(i, n-1, 0) fact_inv[i] = fact_inv[i+1] * mint(i+1);
}
mint comb(int n, int k){ if(n < 0 || k < 0 || n < k) return mint(0); return fact[n] * fact_inv[k] * fact_inv[n-k];}
mint perm(int n, int k){ return comb(n, k) * fact[k]; }
vector<int> prime, pvec;
void make_prime(int n){
    prime.resize(n+1);
    rep(i, 2, n){
        if(prime[i]) continue;
        for(int j = i; j <= n; j+=i) prime[j] = i;
    }
    rep(i, 2, n) if(prime[i] == i) pvec.push_back(i);
}
bool exceed(ll x, ll y, ll m){return x >= m / y + 1;}
void mark(){ cout << "*" << endl; }
void yes(){ cout << "YES" << endl; }
void no(){ cout << "NO" << endl; }
ll floor(ll a, ll b){ if(b < 0) a *= -1, b *= -1; if(a >= 0) return a/b; else return -((-a+b-1)/b); }
ll ceil(ll a, ll b){ if(b < 0) a *= -1, b *= -1; if(a >= 0) return (a+b-1)/b; else return -((-a)/b); }
ll modulo(ll a, ll b){ b = abs(b); return a - floor(a, b) * b; }
ll sgn(ll x){ if(x > 0) return 1; if(x < 0) return -1; return 0;}
ll gcd(ll a, ll b){if(b == 0) return a; return gcd(b, a%b);}
ll lcm(ll a, ll b){return a/gcd(a, b)*b;}
ll digitnum(ll x, ll b = 10){ll ret = 0; for(; x; x /= b) ret++; return ret;}
ll digitsum(ll x, ll b = 10){ll ret = 0; for(; x; x /= b) ret += x % b; return ret;}
string lltos(ll x){string ret; for(;x;x/=10) ret += x % 10 + '0'; reverse(ret.begin(), ret.end()); return ret;}
ll stoll(string &s){ll ret = 0; for(auto c : s) ret *= 10, ret += c - '0'; return ret;}
template<typename T>
void uniq(T &vec){ sort(vec.begin(), vec.end()); vec.erase(unique(vec.begin(), vec.end()), vec.end());}
template<class S, class T> pair<S, T>& operator+=(pair<S,T> &s, const pair<S,T> &t){
    s.first += t.first, s.second += t.second;
    return s;
}
template<class S, class T> pair<S, T>& operator-=(pair<S,T> &s, const pair<S,T> &t){
    s.first -= t.first, s.second -= t.second;
    return s;
}
template<class S, class T> pair<S, T> operator+(const pair<S,T> &s, const pair<S,T> &t){
    return pair<S,T>(s.first+t.first, s.second+t.second);
}
template<class S, class T> pair<S, T> operator-(const pair<S,T> &s, const pair<S,T> &t){
    return pair<S,T>(s.first-t.first, s.second-t.second);
}
template<typename T>
ostream& operator << (ostream& os, vector<T>& vec) {
    reps(i, vec) os << vec[i] << (i + 1 == vec.size() ? "" : " "); return os;
}
template<typename T>
ostream& operator << (ostream& os, const vector<T>& vec) {
    reps(i, vec) os << vec[i] << (i + 1 == vec.size() ? "" : " "); return os;
}
template<typename T>
ostream& operator << (ostream& os, deque<T>& deq) {
    reps(i,  deq) os << deq[i] << (i + 1 == deq.size() ? "" : " "); return os;
}
template<typename T, typename U>
ostream& operator << (ostream& os, pair<T, U>& pair_var) {
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}
template<typename T, typename U>
ostream& operator << (ostream& os, const pair<T, U>& pair_var) {
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}
template<typename T, typename U>
ostream& operator << (ostream& os, map<T, U>& map_var) {
    for(typename map<T, U>::iterator itr = map_var.begin(); itr != map_var.end(); itr++) {
        os << "(" << itr->first << ", " << itr->second << ")";
        itr++; if(itr != map_var.end()) os << ","; itr--;
    }
    return os;
}
template<typename T>
ostream& operator << (ostream& os, set<T>& set_var) {
    for(typename set<T>::iterator itr = set_var.begin(); itr != set_var.end(); itr++) {
        os << *itr; ++itr; if(itr != set_var.end()) os << " "; itr--;
    }
    return os;
}
template<typename T>
ostream& operator << (ostream& os, multiset<T>& set_var) {
    for(typename multiset<T>::iterator itr = set_var.begin(); itr != set_var.end(); itr++) {
        os << *itr; ++itr; if(itr != set_var.end()) os << " "; itr--;
    }
    return os;
}
template<typename T>
void outa(T a[], ll s, ll t){rep(i, s, t){ cout << a[i]; if(i < t) cout << " ";}cout << endl;}
void dump_func(){cout << endl;}
template <class Head, class... Tail>
void dump_func(Head &&head, Tail &&... tail) {
    cout << head;
    if(sizeof...(Tail) > 0) cout << " ";
    dump_func(std::move(tail)...);
}
struct LazySegTree{
    typedef mint SEG;
    typedef mint DELAY;
    
    int size;
    vector<SEG> seg;
    vector<DELAY> delay;
    
    LazySegTree(){}
    LazySegTree(int size){
        this->size = size;
        seg.resize(1<<(size+1));
        delay.resize(1<<(size+1));
    }
    
    SEG Ident(){ //identity element
        return 0;
    }
    SEG ope(SEG a, SEG b){ //operator
        return a+b;
    }
    
    void init()
    {
        for(int i = 0; i < (1<<(size+1)); i++){
            seg[i] = Ident();
            delay[i] = mint(1); //
        }
    }
    
    void eval(int l, int r, int k) //
    {
        if(delay[k] != mint(1)){
            seg[k] *= delay[k];  //総和クエリのときは区間幅を乗じる必要がある
            if(l < r){
                delay[k*2] *= delay[k];
                delay[k*2+1] *= delay[k];
            }
            delay[k] = 1;
        }
    }
    
    void update(int i, SEG val)
    {
        int l = 0, r = (1<<size)-1, k = 1;
        
        eval(l, r, k);
        for(int j = size-1; j >= 0; j--){
            k <<= 1;
            if(i & (1<<j)){
                k++;
                l = (l+r)/2+1;
            }
            else r = (l+r)/2;
            eval(l, r, k);
        }
        
        seg[i+(1<<size)] = val;
        
        l = i, r = i, k = i+(1<<size);
        for(int j = 0; j < size; j++){
            k /= 2, l &= ~(1<<j), r |= 1<<j;
            eval(l, (l+r)/2, k*2), eval((l+r)/2+1, r, k*2+1);
            seg[k] = ope(seg[k*2], seg[k*2+1]);
        }
    }
    
    void add(int a, int b, int k, int l, int r, DELAY val)
    {
        eval(l, r, k);
        
        if(b < l || r < a) return;
        if(a <= l && r <= b){
            delay[k] *= val; //
            eval(l, r, k);
            return;
        }
        add(a, b, k*2, l, (l+r)/2, val);
        add(a, b, k*2+1, (l+r)/2+1, r, val);
        seg[k] = ope(seg[k*2], seg[k*2+1]);
    }
    void add(int a, int b, DELAY val){
        if(a > b) return;
        add(a, b, 1, 0, (1<<size)-1, val);
    }
 
    SEG query(int a, int b, int k, int l, int r)
    {
        eval(l, r, k);
        
        if(b < l || r < a) return Ident();
        if(a <= l && r <= b) return seg[k];
        SEG lval = query(a, b, k*2, l, (l+r)/2);
        SEG rval = query(a, b, k*2+1, (l+r)/2+1, r);
        return ope(lval, rval);
    }
    SEG query(int a, int b)
    {
        if(a > b) return Ident();
        return query(a, b, 1, 0, (1<<size)-1);
    }
};
ll n, m;
ll a[400005];
ll pre[200005];
LazySegTree seg(19), seg2(19);
int main(void)
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    
    cin >> n >> m;
    rep(i, 1, m) cin >> a[n+i];
    rep(i, 1, n) a[i] = n+1-i, pre[n+1-i] = i;
    
    if(n == 1){
        outl(mint(m));
        return 0;
    }
    mint p = mint(n-2) / mint(n);
    
    seg.init(), seg2.init();
    rep(i, 1, n) seg.update(pre[i], 1), seg2.update(pre[i], 1);
    
    mint ans = 0, sum = n;
    rep(i, n+1, n+m){
        if(a[i] != -1){
            ll l = pre[a[i]];
            ans += seg2.query(l+1, i-1);
            ans -= seg.query(0, l-1) * seg2.query(l, l);
            //sum -= seg2.query(l, i-1);
            seg.update(l, 0), seg2.update(l, 0);
            seg.update(i, 1), seg2.update(i, 1);
            pre[a[i]] = i;
        }
        else{
            //ans += sum / n;
            //sum *= p;
            seg2.add(0, i, p);
        }
    }
    ans += mint(n-1) * mint(m);
    ans /= mint(2);
    ans += mint(m);
    
    outl(ans);
    
    return 0;
}
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