QOJ.ac
QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#164068 | #6736. Alice and Bob | yujie3 | TL | 870ms | 132600kb | C++20 | 4.3kb | 2023-09-04 19:22:09 | 2023-09-04 19:22:09 |
Judging History
answer
#include<bits/stdc++.h>
#define endl '\n'
#define fast() ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr)
#define F first
#define S second
#define lowbit(x) ((x) & (-x))
#define _ int _T; cin >> _T; while(_T --)
//#define int long long
#define no cout << "NO" << endl
#define yes cout << "YES" << endl
using namespace std;
typedef pair<int, int> PII;
typedef pair<char,int> PCI;
typedef long long ll;
const int N = 1e7 + 10;
const int MOD = 1e9 + 7;
const ll mod = 998244353;
ll n,m,k;
//int a[N];
//int tree[N];
//int b[N],c[N];
//PII p[N];
//PCI pc[N];
string s;
ll fac[N]; //阶乘
ll inv[N]; //逆元
ll quickMod(ll a,ll b)
{
ll ans = 1;
while (b)
{
if (b&1)
ans = ans * a % mod;
a = a*a % mod;
b >>= 1;
}
return ans;
}
//void getFac()
//{
// fac[0] = inv[0] = 1;
// for (int i = 1 ; i <= N ; i++)
// {
// fac[i] = fac[i-1] * i % mod;
// inv[i] = quickMod(fac[i],mod-2); //表示i的阶乘的逆元
// }
//}
ll getC(ll n,ll m) //C(n,m) = n!/((n-m)!*m!) % (1e9+7)
{
return fac[n] * inv[n-m] % mod;
}
//int fact[N];
//int inv[N];
//
//int qpow(int a,int b,int p)
//{
// int res = 1;
// while (b)
// {
// if (b & 1)
// res = (res * a) % p;
// a = (a * a) % p;
// b /= 2;
// }
// return res % p;
//}
//
//void init()
//{
// fact[0] = 1;
// for (int i = 1; i <= N; i++)
// fact[i] = (fact[i - 1] * i) % mod;
// inv[N] = qpow(fact[N], mod - 2, mod);
// for (int i = N - 1; i >= 0; i--)
// inv[i] = (inv[i + 1] * (i + 1)) % mod;
//}
//
//int _get(int u,int d)
//{
// if(u == 0) return 1;
// int ans = d; u --;
// for(int i = d - 1;u > 0;u --,i --)
// ans *= i,ans %= mod;
// return ans;
//}
void solve()
{
// cin >> n;
// for(int i = 1;i <= n;i ++)
// a[i] = i;
// do
// {
// for(int i = 1;i <= n;i ++)
// cout << a[i] << " ";
// cout << endl;
// }while(next_permutation(a + 1,a + 1 + n));
// cout << "------------------------------------" << endl;
cin >> n;
fac[0] = inv[0] = 1;
for (int i = 1 ; i <= n ; i++)
{
fac[i] = fac[i-1] * i % mod;
inv[i] = quickMod(fac[i],mod-2); //表示i的阶乘的逆元
}
ll ans = 0;
for(int i = 1;i <= n;i ++)
{
if(n - i < i - 1) continue;
ans += getC(n - i,i - 1) * getC(n - i,n - i) % mod;
// ans += fact[n - i] * inv[n - i - (i - 1)] * fact[n - i] % mod;
// ans += _get(i - 1,n - i) * _get(n - i,n - i) % mod;
// cout << ans << " " << i << " " << _get(i - 1,n - i) << " " << _get(n - i,n - i) << "****************" << endl;
// cout << fact[n - i] / fact[n - i - (i - 1)] << " " << fact[n - i] << "--------------- " << fact[n - i - (i - 1)] << " " << fact[n - i] << endl;
}
ans %= mod;
cout << ans << endl;
}
int main()
{
fast();
// _
// init();
// getFac();
solve();
return 0;
}
/**
* ┏┓ ┏┓+ +
* ┏┛┻━━━┛┻┓ + +
* ┃ A C ┃
* ┃ ━ ┃ ++ + + +
* ████━████+
* ◥██◤ ◥██◤ +
* ┃ ┻ ┃
* ┃ ┃ + +
* ┗━┓ ┏━┛
* ┃ ┃ + + + +Code is far away from
* ┃ ┃ + bug with the animal protecting
* ┃ ┗━━━┓ 神兽保佑,代码无bug
* ┃ ┣┓
* ┃ ┏┛
* ┗┓┓┏━┳┓┏┛ + + + +
* ┃┫┫ ┃┫┫
* ┗┻┛ ┗┻┛+ + + +
*/
/*
_ooOoo_
o8888888o
88" . "88
(| -_- |)
O\ = /O
____/`---'\____
.' \\| |// `.
/ \\||| : |||// \
/ _||||| -:- |||||- \
| | \\\ - /// | |
| \_| ''\---/'' | |
\ .-\__ `-` ___/-. /
___`. .' /--.--\ `. . __
."" '< `.___\_<|>_/___.' >'"".
| | : `- \`.;`\ _ /`;.`/ - ` : | |
\ \ `-. \_ __\ /__ _/ .-` / /
======`-.____`-.___\_____/___.-`____.-'======
`=---='
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
A佛祖保佑C
*/
詳細信息
Test #1:
score: 100
Accepted
time: 1ms
memory: 5444kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5448kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 1ms
memory: 5488kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 5460kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 5612kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 5484kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 2ms
memory: 5448kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 5344kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5556kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5552kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5572kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 0ms
memory: 5488kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 0ms
memory: 5584kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 146ms
memory: 27472kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 830ms
memory: 125632kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 870ms
memory: 132600kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 671ms
memory: 104704kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 389ms
memory: 60260kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 766ms
memory: 114000kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 306ms
memory: 51624kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: -100
Time Limit Exceeded
input:
9999998