#860881 (C++17) No.1621 Sequence Inversions

• 問題: No.1621 Sequence Inversions
• ユーザー: akua
• 提出日時: 2023-04-20 12:57:45
• 言語: C++17 (gcc 12.3.0 + boost 1.83.0)
• 結果: AC
• 実行時間: 317 ms / 3,000 ms
• コード長: 5,878 bytes
• コンパイル時間: 5,948 ms
• コンパイル使用メモリ: 236,016 KB
• 実行使用メモリ: 52,740 KB
• 最終ジャッジ日時: 2024-11-15 04:16:45
• 合計ジャッジ時間: 14,020 ms
• ジャッジサーバーID （参考情報）: judge3 / judge5

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	167 ms; 52,740 KB
testcase_01	AC	166 ms; 52,740 KB
testcase_02	AC	166 ms; 52,672 KB
testcase_03	AC	166 ms; 52,612 KB
testcase_04	AC	283 ms; 52,608 KB
testcase_05	AC	165 ms; 52,608 KB
testcase_06	AC	165 ms; 52,608 KB
testcase_07	AC	168 ms; 52,736 KB
testcase_08	AC	317 ms; 52,736 KB
testcase_09	AC	308 ms; 52,660 KB
testcase_10	AC	310 ms; 52,736 KB
testcase_11	AC	313 ms; 52,736 KB
testcase_12	AC	309 ms; 52,608 KB
testcase_13	AC	310 ms; 52,708 KB
testcase_14	AC	306 ms; 52,612 KB
testcase_15	AC	296 ms; 52,704 KB
testcase_16	AC	262 ms; 52,576 KB
testcase_17	AC	291 ms; 52,580 KB
testcase_18	AC	257 ms; 52,616 KB
testcase_19	AC	166 ms; 52,708 KB
testcase_20	AC	195 ms; 52,704 KB
testcase_21	AC	294 ms; 52,572 KB
testcase_22	AC	295 ms; 52,616 KB
testcase_23	AC	297 ms; 52,704 KB
testcase_24	AC	166 ms; 52,612 KB
testcase_25	AC	165 ms; 52,484 KB
testcase_26	AC	167 ms; 52,708 KB
testcase_27	AC	167 ms; 52,576 KB
testcase_28	AC	165 ms; 52,612 KB

ソースコード

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <atcoder/all>
#include <iostream> // cout, endl, cin
#include <string> // string, to_string, stoi
#include <vector> // vector
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <utility> // pair, make_pair
#include <tuple> // tuple, make_tuple
#include <cstdint> // int64_t, int*_t
#include <cstdio> // printf
#include <map> // map
#include <queue> // queue, priority_queue
#include <set> // set
#include <stack> // stack
#include <deque> // deque
#include <unordered_map> // unordered_map
#include <unordered_set> // unordered_set
#include <bitset> // bitset
#include <cctype> // isupper, islower, isdigit, toupper, tolower
#include <math.h>
#include <iomanip>
#include <functional>
using namespace std;  
using namespace atcoder;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repi(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
typedef long long ll;
typedef unsigned long long ull;
const ll inf=1e18;  
using graph = vector<vector<int> > ;
using P= pair<ll,ll>;  
using vi=vector<int>;
using vvi=vector<vi>;
using vll=vector<ll>; 
using vvll=vector<vll>;
using vp=vector<P>;
using vvp=vector<vp>;
using vd=vector<double>;
using vvd =vector<vd>;
//string T="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
//string S="abcdefghijklmnopqrstuvwxyz";
//g++ main.cpp -std=c++17 -I .  
//cout <<setprecision(20);
//cout << fixed << setprecision(10);
//cin.tie(0); ios::sync_with_stdio(false);
const double PI = acos(-1);
int vx[]={0,1,0,-1,-1,1,1,-1},vy[]={1,0,-1,0,1,1,-1,-1};
void putsYes(bool f){cout << (f?"Yes":"No") << endl;}
void putsYES(bool f){cout << (f?"YES":"NO") << endl;}
void putsFirst(bool f){cout << (f?"First":"Second") << endl;}
void debug(int test){cout << "TEST" << " " << test << endl;}
ll pow_pow(ll x,ll n,ll mod){
    if(n==0) return 1; 
    x%=mod;
    ll res=pow_pow(x*x%mod,n/2,mod);
    if(n&1)res=res*x%mod;
    return res;
}
ll gcd(ll x,ll y){
    if(y==0)return x;
    return gcd(y,x%y);
}
 
ll lcm(ll x,ll y){
    return ll(x/gcd(x,y))*y;
}
template<class T> bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    else return false;
}
template<class T> bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    else return false;
}
// https://youtu.be/L8grWxBlIZ4?t=9858
// https://youtu.be/ERZuLAxZffQ?t=4807 : optimize
// https://youtu.be/8uowVvQ_-Mo?t=1329 : division
ll mod =998244353;
//ll mod =1e9+7;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
 
  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}
// combination mod prime
// https://www.youtube.com/watch?v=8uowVvQ_-Mo&feature=youtu.be&t=1619
struct combination {
  vector<mint> fact, ifact;
  combination(int n):fact(n+1),ifact(n+1) {
    //assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    if (n<0) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  } mint p(int n, int k) { return fact[n]*ifact[n-k]; } } c(2000000); 
using vm=vector<mint> ;
using vvm=vector<vm> ;
struct edge{
  int to; ll cost;
  edge(int to,ll cost) : to(to),cost(cost){}
};
using ve=vector<edge>;
using vve=vector<ve>;
struct Compress{
   vll a;
   map<ll,ll> d,d2;
   int cnt;
   Compress() :cnt(0) {}
   void add(ll x){a.push_back(x);}
   void init(){
     set<ll>s(a.begin(),a.end());
     for(auto y:s)d[y]=cnt++;
     for(auto&y:a)y=d[y];
     for(auto u:d)d2[u.second]=u.first;
   }
   ll to(ll x){return d[x];} //変換先
   ll from(ll x){return d2[x];}//逆引き
   int size(){return cnt;}
};
vll anss;
const int N=105;
mint dp[N*N][N];
mint dpsum[N*N][N];
void solve(int test){
  int n,k; cin >> n >> k;
  vi a(n);rep(i,n)cin >> a[i];
  Compress comp;
  rep(i,n)comp.add(a[i]);
  comp.init();
  rep(i,n)a[i]=comp.to(a[i]);
  vi cnt(n);
  sort(a.rbegin(),a.rend());
  dpsum[0][1]=1;
  {
    rep(j,n*(n-1)/2+1)repi(last,1,n+1)dpsum[j][last]+=dpsum[j][last-1];
  }
  cnt[a[0]]++;
  repi(i,2,n+1){
    rep(j,n*(n-1)/2+1)repi(last,1,i+1){
      if(cnt[a[i-1]]==0){
       int prej=j-(last-1);
       if(prej>=0)dp[j][last]+=dpsum[prej][n];
       else dp[j][last]=0;
      }
      else {
        int prej=j-(last-1-cnt[a[i-1]]);
        if(prej>=0 && last!=1)dp[j][last]+=dpsum[prej][last-1];
        else dp[j][last]=0;
      }
    }
    cnt[a[i-1]]++;
    rep(j,n*(n-1)/2+1)repi(last,1,n+1)dpsum[j][last]=0;
    rep(j,n*(n-1)/2+1)repi(last,1,n+1)dpsum[j][last]=dpsum[j][last-1]+dp[j][last];
    rep(j,n*(n-1)/2+1)repi(last,1,i+1)dp[j][last]=0;
  }
  mint ans=dpsum[k][n];
  cout << ans << endl;
}
//g++ main.cpp -std=c++17 -I .
int main(){cin.tie(0);ios::sync_with_stdio(false);
  int t=1;//cin >> t;
  rep(test,t)solve(test);
  for(auto u:anss)cout << u << endl;
}