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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#360783#6736. Alice and Bob1366397866TL 0ms0kbC++141.5kb2024-03-22 08:48:182024-03-22 08:48:19

Judging History

你现在查看的是最新测评结果

  • [2024-03-22 08:48:19]
  • 评测
  • 测评结果:TL
  • 用时:0ms
  • 内存:0kb
  • [2024-03-22 08:48:18]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
#define endl "\n"
#define PII pair<int,int>
#define int long long
const int N=1e7+10;
const int INF=1e18;
namespace DEBUG {
template <typename T>
void _debug(const char* format, T t) {
  cerr << format << '=' << t << endl;
}
template <class First, class... Rest>
void _debug(const char* format, First first, Rest... rest) {
  while (*format != ',') cerr << *format++;
  cerr << '=' << first << ",";
  _debug(format + 1, rest...);
}
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& V) {
  os << "[ ";
  for (const auto& vv : V) os << vv << ", ";
  os << "]";
  return os;
}
#define debug(...) _debug(#__VA_ARGS__, __VA_ARGS__)
}  // namespace DEBUG

using namespace DEBUG;
const int mod=998244353;
int jc[N],invjc[N];
int q_pow(int a, int k, int p) {
	int res = 1;
	while (k) {
		if (k & 1) res = res * a % p;
		a = a * a % p;
		k >>= 1;
	}
	return res;
}
void init()
{
    jc[0]=1;
    invjc[0]=1;
    for(int i=1;i<N;i++)
    {
        jc[i]=jc[i-1]*i%mod;
        invjc[i]=invjc[i-1]*q_pow(i,mod-2,mod)%mod;
    }
}
int C(int a,int b)
{
    if(a<b)return 0;
    return jc[a]*invjc[b]%mod*invjc[a-b]%mod;
}
void solve()
{
	int n;
	cin>>n;
	int sum=0;
	for(int i=1;i<=n;i++)
	{
		if(n-i<i-1)break;
		sum=(sum+(C(n-i,i-1)*jc[i-1]%mod*jc[n-i]%mod))%mod;
	}
	cout<<sum%mod<<endl;
}
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int T=1;
	init();
//	cin>>T;
	while(T--)solve();
	return 0; 
} 

Details

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Test #1:

score: 0
Time Limit Exceeded

input:

1

output:

1

result: