#1152814 (C++17) No.1621 Sequence Inversions

• 問題: No.1621 Sequence Inversions
• ユーザー: 👑 AngrySadEight
• 提出日時: 2026-03-19 02:15:46
• 言語: C++17 (gcc 15.2.0 + boost 1.89.0)
• 結果: AC
• 実行時間: 1,149 ms / 3,000 ms
• コード長: 4,162 bytes
• コンパイル時間: 4,828 ms
• コンパイル使用メモリ: 228,928 KB
• 実行使用メモリ: 55,904 KB
• 最終ジャッジ日時: 2026-03-19 02:15:57
• 合計ジャッジ時間: 10,656 ms
• ジャッジサーバーID （参考情報）: judge1_0 / judge3_0

ファイルパターン	結果
sample	AC * 3
other	AC * 26

ソースコード

#include <algorithm>
#include <atcoder/all>
#include <bitset>
#include <cassert>
#include <cmath>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int, int>
#define pil pair<int, ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int, int>>
#define vpll vector<pair<ll, ll>>
#define vvpii vector<vector<pair<int, int>>>
#define vvpll vector<vector<pair<ll, ll>>>

template <typename T>
void debug(T e) {
    cerr << e << endl;
}

template <typename T>
void debug(vector<T> &v) {
    rep(i, v.size()) { cerr << v[i] << " "; }
    cerr << endl;
}

template <typename T>
void debug(vector<vector<T>> &v) {
    rep(i, v.size()) {
        rep(j, v[i].size()) { cerr << v[i][j] << " "; }
        cerr << endl;
    }
}

template <typename T>
void debug(vector<pair<T, T>> &v) {
    rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; }
}

template <typename T>
void debug(set<T> &st) {
    for (auto itr = st.begin(); itr != st.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(multiset<T> &ms) {
    for (auto itr = ms.begin(); itr != ms.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(map<T, T> &mp) {
    for (auto itr = mp.begin(); itr != mp.end(); itr++) {
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << H << " ";
    debug_out(T...);
}

using mint = modint998244353;

void debug_mint1(vector<mint> &vec) {
    for (int i = 0; i < vec.size(); i++) {
        cerr << vec[i].val() << " ";
    }
    cerr << endl;
}

void debug_mint2(vector<vector<mint>> &vec) {
    for (int i = 0; i < vec.size(); i++) {
        for (int j = 0; j < vec[i].size(); j++) {
            cerr << vec[i][j].val() << " ";
        }
        cerr << endl;
    }
}

int main() {
    ll N, K;
    cin >> N >> K;
    vector<ll> A(N);
    rep(i, N) cin >> A[i];
    
    map<ll, ll> mp;
    for (ll i = 0; i < N; i++){
        mp[A[i]]++;
    }

    vector<mint> dp(K + 1, mint(0));
    dp[0] = mint(1);

    ll now_times = 0;
    for (auto it = mp.begin(); it != mp.end(); it++){
        // 内部で小さい dp をさらに動かす
        ll cnt = (it->second);
        vector<vector<vector<mint>>> subdp(now_times + 2, vector<vector<mint>>(cnt + 1, vector<mint>(K + 1)));
        subdp[0][0][0] = mint(1);
        for (ll i = 0; i <= now_times; i++){
            for (ll j = 0; j <= cnt; j++){
                for (ll k = 0; k + j <= cnt; k++){
                    for (ll l = 0; l + k * (now_times - i) <= K; l++){
                        subdp[i + 1][k + j][l + k * (now_times - i)] += subdp[i][j][l];
                    }
                }
            }
        }
        vector<mint> new_dp(K + 1, mint(0));
        for (ll i = 0; i <= K; i++){
            for (ll j = 0; j + i <= K; j++){
                new_dp[i + j] += subdp[now_times + 1][cnt][j] * dp[i];
            }
        }
        for (ll j = 0; j <= K; j++){
            dp[j] = new_dp[j];
        }
        // debug_mint1(dp);

        now_times += cnt;
    }
    cout << dp[K].val() << endl;
}