結果
問題 | No.2484 Add to Variables |
ユーザー |
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提出日時 | 2023-09-22 22:47:22 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 132 ms / 2,000 ms |
コード長 | 2,167 bytes |
コンパイル時間 | 4,587 ms |
コンパイル使用メモリ | 261,292 KB |
最終ジャッジ日時 | 2025-02-17 00:58:29 |
ジャッジサーバーID (参考情報) |
judge1 / judge1 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 4 |
other | AC * 39 |
ソースコード
#include<bits/stdc++.h>using namespace std;//* ATCODER#include<atcoder/all>using namespace atcoder;typedef modint998244353 mint;//*//* BOOST MULTIPRECISION#include<boost/multiprecision/cpp_int.hpp>using namespace boost::multiprecision;//*/typedef long long ll;#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)template <typename T> bool chmin(T &a, const T &b) {if (a <= b) return false;a = b;return true;}template <typename T> bool chmax(T &a, const T &b) {if (a >= b) return false;a = b;return true;}template <typename T> T max(vector<T> &a){assert(!a.empty());T ret = a[0];for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);return ret;}template <typename T> T min(vector<T> &a){assert(!a.empty());T ret = a[0];for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);return ret;}template <typename T> T sum(vector<T> &a){T ret = 0;for (int i=0; i<(int)a.size(); i++) ret += a[i];return ret;}//defmodfactconst int COMinitMAX = 998244;mint fact[COMinitMAX+1], factinv[COMinitMAX+1];void modfact(){fact[0] = 1;for (int i=1; i<=COMinitMAX; i++){fact[i] = fact[i-1] * i;}factinv[COMinitMAX] = fact[COMinitMAX].inv();for (int i=COMinitMAX-1; i>=0; i--){factinv[i] = factinv[i+1] * (i+1);}}mint cmb(int a, int b){if (a<b || b<0) return mint(0);return fact[a]*factinv[b]*factinv[a-b];}//--------int main(){modfact();int n, m; cin >> n >> m;vector<int> b(n);rep(i,0,n) cin >> b[i];int a = m-b[0];vector<vector<mint>> dp(n, vector<mint>(a+1));dp[0][0] = 1;rep(i,1,n){vector<mint> x(a+1);vector<mint> y(a+1);rep(k,0,a+1){if (b[i-1]-k >= 0){x[k] = dp[i-1][k] * factinv[k] * fact[b[i-1]-k];}}rep(k,0,a+1){if (b[i-1]-b[i]+k >= 0){y[k] = factinv[k] * factinv[b[i-1]-b[i]+k];}}vector<mint> z = convolution(x, y);rep(j,0,a+1){if (b[i]-j >= 0){dp[i][j] = fact[j] * factinv[b[i]-j] * z[j];}}}mint ans = 0;rep(j,0,a+1){ans += dp[n-1][j] * cmb(m, b[0] + j) * cmb(b[0] + j, b[0]);}cout << ans.val() << '\n';}