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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#176258#6417. Classical Summation ProblemLiberty12619AC ✓130ms19348kbC++201.1kb2023-09-11 13:50:002023-09-11 13:50:00

Judging History

你现在查看的是最新测评结果

  • [2023-09-11 13:50:00]
  • 评测
  • 测评结果:AC
  • 用时:130ms
  • 内存:19348kb
  • [2023-09-11 13:50:00]
  • 提交

answer

#include <bits/stdc++.h>
#define x first
#define y second
#define int long long
using namespace std;
typedef pair<int,int> PII;
const int N = 1e6 + 10,INF=1e12,mod = 998244353;
int fact[N],infact[N];
int qmi(int a,int b)
{
    int res=1;
    while(b)
    {
        if(b&1) res=res*a%mod;
        a=a*a%mod;
        b>>=1;
    }
    return res;
}
void init()
{
    fact[0]=infact[0]=1;
    for(int i=1;i<N;i++)fact[i]=fact[i-1]*i%mod;
    infact[N-1]=qmi(fact[N-1],mod-2);
    for(int i=N-2;i>0;i--) infact[i]=infact[i+1]*(i+1)%mod;
}
int C(int a,int b)
{
    if(a<b) return 0;
    return fact[a]*infact[b]%mod*infact[a-b]%mod;
}
void solve()
{
    int n,k;
    cin>>n>>k;
    if(k&1)
    {
        cout<<(n+1)*infact[2]%mod*qmi(n,k)%mod<<"\n";
        return;
    }
    int res=0;
    for(int i=1;i<n;i++)    res+=qmi(i,k/2)*qmi(n-i,k/2)%mod*C(k,k/2)%mod;
    res = ((n+1)*infact[2]%mod*qmi(n,k)%mod-res%mod*infact[2]%mod+mod)%mod;
    cout<<res<<"\n";
}

signed main()
{
    int T=1;
    cin.tie(0)->sync_with_stdio(false);
    //cin>>T;
    init();
    while(T--)
    {
        solve();
    }
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 3ms
memory: 19292kb

input:

3 2

output:

14

result:

ok 1 number(s): "14"

Test #2:

score: 0
Accepted
time: 7ms
memory: 19296kb

input:

5 3

output:

375

result:

ok 1 number(s): "375"

Test #3:

score: 0
Accepted
time: 11ms
memory: 19296kb

input:

2 2

output:

5

result:

ok 1 number(s): "5"

Test #4:

score: 0
Accepted
time: 3ms
memory: 19276kb

input:

10 9

output:

508778235

result:

ok 1 number(s): "508778235"

Test #5:

score: 0
Accepted
time: 7ms
memory: 19220kb

input:

69 3

output:

11497815

result:

ok 1 number(s): "11497815"

Test #6:

score: 0
Accepted
time: 11ms
memory: 19280kb

input:

994 515

output:

33689623

result:

ok 1 number(s): "33689623"

Test #7:

score: 0
Accepted
time: 7ms
memory: 19340kb

input:

4476 6182

output:

114894183

result:

ok 1 number(s): "114894183"

Test #8:

score: 0
Accepted
time: 7ms
memory: 19340kb

input:

58957 12755

output:

932388891

result:

ok 1 number(s): "932388891"

Test #9:

score: 0
Accepted
time: 18ms
memory: 19264kb

input:

218138 28238

output:

392861201

result:

ok 1 number(s): "392861201"

Test #10:

score: 0
Accepted
time: 73ms
memory: 19268kb

input:

644125 316810

output:

420621854

result:

ok 1 number(s): "420621854"

Test #11:

score: 0
Accepted
time: 80ms
memory: 19280kb

input:

612914 505428

output:

973686286

result:

ok 1 number(s): "973686286"

Test #12:

score: 0
Accepted
time: 11ms
memory: 19220kb

input:

998216 938963

output:

251335926

result:

ok 1 number(s): "251335926"

Test #13:

score: 0
Accepted
time: 3ms
memory: 19276kb

input:

990516 996933

output:

549551960

result:

ok 1 number(s): "549551960"

Test #14:

score: 0
Accepted
time: 129ms
memory: 19348kb

input:

999019 999012

output:

637189128

result:

ok 1 number(s): "637189128"

Test #15:

score: 0
Accepted
time: 130ms
memory: 19276kb

input:

999928 999950

output:

185229465

result:

ok 1 number(s): "185229465"

Test #16:

score: 0
Accepted
time: 7ms
memory: 19292kb

input:

999999 999999

output:

384164916

result:

ok 1 number(s): "384164916"

Test #17:

score: 0
Accepted
time: 120ms
memory: 19264kb

input:

999999 1000000

output:

696165930

result:

ok 1 number(s): "696165930"

Test #18:

score: 0
Accepted
time: 11ms
memory: 19280kb

input:

1000000 999999

output:

219071706

result:

ok 1 number(s): "219071706"

Test #19:

score: 0
Accepted
time: 116ms
memory: 19348kb

input:

1000000 1000000

output:

128206597

result:

ok 1 number(s): "128206597"

Test #20:

score: 0
Accepted
time: 7ms
memory: 19292kb

input:

2 10

output:

1410

result:

ok 1 number(s): "1410"

Test #21:

score: 0
Accepted
time: 3ms
memory: 19280kb

input:

84 16

output:

297627153

result:

ok 1 number(s): "297627153"

Test #22:

score: 0
Accepted
time: 3ms
memory: 19284kb

input:

643 800

output:

489237163

result:

ok 1 number(s): "489237163"

Test #23:

score: 0
Accepted
time: 8ms
memory: 19344kb

input:

9903 880

output:

595167333

result:

ok 1 number(s): "595167333"

Test #24:

score: 0
Accepted
time: 16ms
memory: 19288kb

input:

97446 89750

output:

410205549

result:

ok 1 number(s): "410205549"

Test #25:

score: 0
Accepted
time: 32ms
memory: 19228kb

input:

186460 646474

output:

32638530

result:

ok 1 number(s): "32638530"

Test #26:

score: 0
Accepted
time: 65ms
memory: 19276kb

input:

508940 244684

output:

598321755

result:

ok 1 number(s): "598321755"

Test #27:

score: 0
Accepted
time: 61ms
memory: 19340kb

input:

583646 557758

output:

858695621

result:

ok 1 number(s): "858695621"

Test #28:

score: 0
Accepted
time: 113ms
memory: 19344kb

input:

969610 992608

output:

256683498

result:

ok 1 number(s): "256683498"

Test #29:

score: 0
Accepted
time: 115ms
memory: 19296kb

input:

995106 996434

output:

411791999

result:

ok 1 number(s): "411791999"

Test #30:

score: 0
Accepted
time: 121ms
memory: 19288kb

input:

999961 999872

output:

61222370

result:

ok 1 number(s): "61222370"

Test #31:

score: 0
Accepted
time: 130ms
memory: 19284kb

input:

999977 999908

output:

831096762

result:

ok 1 number(s): "831096762"

Test #32:

score: 0
Accepted
time: 130ms
memory: 19316kb

input:

999992 999998

output:

562977678

result:

ok 1 number(s): "562977678"

Test #33:

score: 0
Accepted
time: 14ms
memory: 19208kb

input:

1000000 2

output:

118436113

result:

ok 1 number(s): "118436113"

Test #34:

score: 0
Accepted
time: 7ms
memory: 19292kb

input:

2 1000000

output:

298823641

result:

ok 1 number(s): "298823641"