結果
問題 | No.2068 Restricted Permutation |
ユーザー |
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提出日時 | 2022-09-02 23:11:16 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 43 ms / 2,000 ms |
コード長 | 1,733 bytes |
コンパイル時間 | 3,888 ms |
コンパイル使用メモリ | 257,304 KB |
最終ジャッジ日時 | 2025-02-07 01:51:15 |
ジャッジサーバーID (参考情報) |
judge5 / judge5 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 23 |
ソースコード
#include <stdio.h>#include <atcoder/all>#include <bits/stdc++.h>using namespace std;using namespace atcoder;using mint = modint998244353;#define rep(i,n) for (int i = 0; i < (n); ++i)#define Inf32 1000000001#define Inf64 2000000000000000001struct combi{deque<mint> kaijou;deque<mint> kaijou_;combi(int n){kaijou.push_back(1);for(int i=1;i<=n;i++){kaijou.push_back(kaijou[i-1]*i);}mint b=kaijou[n].inv();kaijou_.push_front(b);for(int i=1;i<=n;i++){int k=n+1-i;kaijou_.push_front(kaijou_[0]*k);}}mint combination(int n,int r){if(r>n)return 0;mint a = kaijou[n]*kaijou_[r];a *= kaijou_[n-r];return a;}mint junretsu(int a,int b){mint x = kaijou_[a]*kaijou_[b];x *= kaijou[a+b];return x;}mint catalan(int n){return combination(2*n,n)/(n+1);}};mint sum(mint N){mint ret = N;ret *= N+1;ret /= 2;return ret;}int main(){int N,K,X;cin>>N>>K>>X;mint ans = 0;combi C(500000);for(int i=0;i<=N-2;i++){mint t = 1;if(i>=K)t *= C.combination(N-1,i-1) * C.kaijou[i-1];else t *= C.combination(N-1,i) * C.kaijou[i];//cout<<t.val()<<endl;if(i+1<K){mint tt = C.combination(N-i-1,2);{mint ttt = N-i-1;ttt *= N-X;ttt /= N-1;tt += ttt;//cout<<ttt.val()<<endl;}tt *= C.kaijou[N-i-1];tt *= C.kaijou[N-i-2];t *= tt;ans += t;}else if(i+1==K){mint tt = N-i-1;tt *= X-1;tt /= N-1;tt *= C.kaijou[N-i-1];tt *= C.kaijou[N-i-1];t *= tt;ans += t;}else{mint tt = C.combination(N-i,2);tt *= C.kaijou[N-i-1];tt *= C.kaijou[N-i-1];t *= tt;ans += t;}}cout<<ans.val()<<endl;return 0;}