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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
#197514#6417. Classical Summation Problemucup-team870#AC ✓46ms19304kbC++141.0kb2023-10-02 16:39:462023-10-02 16:39:46

Judging History

你现在查看的是最新测评结果

  • [2023-10-02 16:39:46]
  • 评测
  • 测评结果:AC
  • 用时:46ms
  • 内存:19304kb
  • [2023-10-02 16:39:46]
  • 提交

answer

#include <bits/stdc++.h>
#define rep(i,l,r) for(int i=l; i<=r; i++)
#define per(i,r,l) for(int i=r; i>=l; i--)
#define IOS {cin.tie(0);cout.tie(0);ios::sync_with_stdio(0);}
using namespace std;
typedef long long ll;
const int N=1e6+6,mod=998244353;
void add(ll &x,ll y){x=(x+y)%mod;}
ll qp(ll x,ll y){
    ll res=1;
    while(y){
        if(y&1)res=res*x%mod;
        x=x*x%mod; y>>=1;
    }
    return res;
}
ll fac[N],inv[N];
ll C(int i,int j){
    return fac[i]*inv[j]%mod*inv[i-j]%mod;
}
int main() {
    const int M=1e6;
    fac[0]=1; rep(i,1,M)fac[i]=fac[i-1]*i%mod;
    inv[M]=qp(fac[M],mod-2); per(i,M,1)inv[i-1]=inv[i]*i%mod;
    int n,k;cin>>n>>k;
    ll ans=0,nk=qp(n,k);
    rep(i,1,n/2){
        if(i*2==n)break;
        if(k&1){
            add(ans,nk);
        }
        else{
            add(ans,nk+C(k,k/2)*qp(1ll*i*(n-i)%mod,k/2) );
        }
    }
    if(n%2==0){
        int x=n/2; ll v=qp(x,k);
        rep(i,(k+1)/2,k)add(ans,C(k,i)*v%mod);
    }
    cout<<(n*nk-ans+mod)%mod;
    return 0;
}

详细

Test #1:

score: 100
Accepted
time: 11ms
memory: 19148kb

input:

3 2

output:

14

result:

ok 1 number(s): "14"

Test #2:

score: 0
Accepted
time: 6ms
memory: 19300kb

input:

5 3

output:

375

result:

ok 1 number(s): "375"

Test #3:

score: 0
Accepted
time: 9ms
memory: 19112kb

input:

2 2

output:

5

result:

ok 1 number(s): "5"

Test #4:

score: 0
Accepted
time: 10ms
memory: 19148kb

input:

10 9

output:

508778235

result:

ok 1 number(s): "508778235"

Test #5:

score: 0
Accepted
time: 6ms
memory: 19144kb

input:

69 3

output:

11497815

result:

ok 1 number(s): "11497815"

Test #6:

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

input:

994 515

output:

33689623

result:

ok 1 number(s): "33689623"

Test #7:

score: 0
Accepted
time: 7ms
memory: 19284kb

input:

4476 6182

output:

114894183

result:

ok 1 number(s): "114894183"

Test #8:

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

input:

58957 12755

output:

932388891

result:

ok 1 number(s): "932388891"

Test #9:

score: 0
Accepted
time: 11ms
memory: 19236kb

input:

218138 28238

output:

392861201

result:

ok 1 number(s): "392861201"

Test #10:

score: 0
Accepted
time: 25ms
memory: 19208kb

input:

644125 316810

output:

420621854

result:

ok 1 number(s): "420621854"

Test #11:

score: 0
Accepted
time: 30ms
memory: 19204kb

input:

612914 505428

output:

973686286

result:

ok 1 number(s): "973686286"

Test #12:

score: 0
Accepted
time: 10ms
memory: 19232kb

input:

998216 938963

output:

251335926

result:

ok 1 number(s): "251335926"

Test #13:

score: 0
Accepted
time: 3ms
memory: 19220kb

input:

990516 996933

output:

549551960

result:

ok 1 number(s): "549551960"

Test #14:

score: 0
Accepted
time: 44ms
memory: 19228kb

input:

999019 999012

output:

637189128

result:

ok 1 number(s): "637189128"

Test #15:

score: 0
Accepted
time: 41ms
memory: 19108kb

input:

999928 999950

output:

185229465

result:

ok 1 number(s): "185229465"

Test #16:

score: 0
Accepted
time: 9ms
memory: 19232kb

input:

999999 999999

output:

384164916

result:

ok 1 number(s): "384164916"

Test #17:

score: 0
Accepted
time: 39ms
memory: 19276kb

input:

999999 1000000

output:

696165930

result:

ok 1 number(s): "696165930"

Test #18:

score: 0
Accepted
time: 14ms
memory: 19280kb

input:

1000000 999999

output:

219071706

result:

ok 1 number(s): "219071706"

Test #19:

score: 0
Accepted
time: 44ms
memory: 19168kb

input:

1000000 1000000

output:

128206597

result:

ok 1 number(s): "128206597"

Test #20:

score: 0
Accepted
time: 11ms
memory: 19108kb

input:

2 10

output:

1410

result:

ok 1 number(s): "1410"

Test #21:

score: 0
Accepted
time: 5ms
memory: 19244kb

input:

84 16

output:

297627153

result:

ok 1 number(s): "297627153"

Test #22:

score: 0
Accepted
time: 10ms
memory: 19280kb

input:

643 800

output:

489237163

result:

ok 1 number(s): "489237163"

Test #23:

score: 0
Accepted
time: 7ms
memory: 19152kb

input:

9903 880

output:

595167333

result:

ok 1 number(s): "595167333"

Test #24:

score: 0
Accepted
time: 6ms
memory: 19220kb

input:

97446 89750

output:

410205549

result:

ok 1 number(s): "410205549"

Test #25:

score: 0
Accepted
time: 17ms
memory: 19148kb

input:

186460 646474

output:

32638530

result:

ok 1 number(s): "32638530"

Test #26:

score: 0
Accepted
time: 21ms
memory: 19304kb

input:

508940 244684

output:

598321755

result:

ok 1 number(s): "598321755"

Test #27:

score: 0
Accepted
time: 20ms
memory: 19296kb

input:

583646 557758

output:

858695621

result:

ok 1 number(s): "858695621"

Test #28:

score: 0
Accepted
time: 41ms
memory: 19284kb

input:

969610 992608

output:

256683498

result:

ok 1 number(s): "256683498"

Test #29:

score: 0
Accepted
time: 46ms
memory: 19244kb

input:

995106 996434

output:

411791999

result:

ok 1 number(s): "411791999"

Test #30:

score: 0
Accepted
time: 42ms
memory: 19280kb

input:

999961 999872

output:

61222370

result:

ok 1 number(s): "61222370"

Test #31:

score: 0
Accepted
time: 40ms
memory: 19220kb

input:

999977 999908

output:

831096762

result:

ok 1 number(s): "831096762"

Test #32:

score: 0
Accepted
time: 42ms
memory: 19112kb

input:

999992 999998

output:

562977678

result:

ok 1 number(s): "562977678"

Test #33:

score: 0
Accepted
time: 10ms
memory: 19236kb

input:

1000000 2

output:

118436113

result:

ok 1 number(s): "118436113"

Test #34:

score: 0
Accepted
time: 13ms
memory: 19304kb

input:

2 1000000

output:

298823641

result:

ok 1 number(s): "298823641"