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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 |
---|---|---|---|---|---|---|---|---|---|
#411719 | #6736. Alice and Bob | Ynoiynoi# | AC ✓ | 127ms | 159928kb | C++17 | 768b | 2024-05-15 18:45:06 | 2024-05-15 18:45:06 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N = 1e7+10, MO = 998244353;
LL n, fac[N], facInv[N];
LL qpm(LL a, LL b) {
LL ans = 1;
while(b) {
if(b & 1) ans = ans * a % MO;
a = a * a % MO;
b >>= 1;
}
return ans;
}
LL A(int n, int m) {
if(m < 0) return 0;
if(n < m) return 0;
return fac[n] * facInv[n-m] % MO;
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n;
fac[0] = 1;
for(int i = 1; i <= n; i ++) fac[i] = fac[i-1] * i % MO;
facInv[n] = qpm(fac[n], MO-2);
for(int i = n-1; i >= 0; i --) facInv[i] = facInv[i+1] * (i+1) % MO;
LL ans = 0;
for(int i = 1; i <= n; i ++) {
ans = (ans + A(n-i, i-1) * A(n-i, n-i) % MO) % MO;
}
cout << ans << '\n';
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 1ms
memory: 5656kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5780kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 0ms
memory: 5720kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 5696kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 0ms
memory: 5720kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 0ms
memory: 5732kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 5776kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 5716kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 0ms
memory: 5660kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5736kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5780kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 5728kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 5740kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 20ms
memory: 26928kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 84ms
memory: 122692kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 97ms
memory: 132964kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 71ms
memory: 101784kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 42ms
memory: 61136kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 72ms
memory: 114424kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 27ms
memory: 52328kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 127ms
memory: 159856kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 111ms
memory: 159916kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 114ms
memory: 159928kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"