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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#407931#6417. Classical Summation Problemgrass8cow#AC ✓53ms11756kbC++171.1kb2024-05-09 15:00:132024-05-09 15:00:14

Judging History

你现在查看的是最新测评结果

  • [2024-05-09 15:00:14]
  • 评测
  • 测评结果:AC
  • 用时:53ms
  • 内存:11756kb
  • [2024-05-09 15:00:13]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
int n,m;
const int mod=998244353;
int qpow(int a,int b){
    int c=1;
    for(;b;b>>=1){
        if(b&1)c=1ll*a*c%mod;
        a=1ll*a*a%mod;
    }
    return c;
}
const int N=1e6;
int jc[1010000],ij[1010000];
int C(int a,int b){
    if(a<0||a<b||b<0)return 0;
    return 1ll*jc[a]*ij[b]%mod*ij[a-b]%mod;
}
void sieve(){
    jc[0]=1;
    for(int i=1;i<=N;i++)jc[i]=1ll*i*jc[i-1]%mod;
    ij[N]=qpow(jc[N],mod-2);
    for(int i=N;i;i--)ij[i-1]=1ll*i*ij[i]%mod;
}
int main(){
    sieve();
    scanf("%d%d",&n,&m);
    int ans=0;
    /*for(int t=1;t<n;t++)for(int i=0;i<=(m-1)/2;i++)
    (ans+=1ll*C(m,i)*qpow(t,i)%mod*qpow(n-t,m-i)%mod)%=mod;*/
    int al=qpow(n,m);
    for(int t=1;t*2<n;t++){
        (ans+=al)%=mod;
        if(!(m&1))(ans-=1ll*C(m,m/2)*qpow(1ll*t*(n-t)%mod,m/2)%mod)%=mod;
        //同时计算t和n-t的贡献
    }
    if(!(n&1)){
        int zk=qpow(n/2,m);
        for(int i=0;i<=(m-1)/2;i++)(ans+=1ll*C(m,i)*zk%mod)%=mod;
    }
    printf("%d\n",((ans+qpow(n,m))%mod+mod)%mod);
    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 12ms
memory: 11636kb

input:

3 2

output:

14

result:

ok 1 number(s): "14"

Test #2:

score: 0
Accepted
time: 12ms
memory: 11672kb

input:

5 3

output:

375

result:

ok 1 number(s): "375"

Test #3:

score: 0
Accepted
time: 12ms
memory: 11488kb

input:

2 2

output:

5

result:

ok 1 number(s): "5"

Test #4:

score: 0
Accepted
time: 12ms
memory: 11684kb

input:

10 9

output:

508778235

result:

ok 1 number(s): "508778235"

Test #5:

score: 0
Accepted
time: 9ms
memory: 11608kb

input:

69 3

output:

11497815

result:

ok 1 number(s): "11497815"

Test #6:

score: 0
Accepted
time: 12ms
memory: 11724kb

input:

994 515

output:

33689623

result:

ok 1 number(s): "33689623"

Test #7:

score: 0
Accepted
time: 8ms
memory: 11656kb

input:

4476 6182

output:

114894183

result:

ok 1 number(s): "114894183"

Test #8:

score: 0
Accepted
time: 8ms
memory: 11508kb

input:

58957 12755

output:

932388891

result:

ok 1 number(s): "932388891"

Test #9:

score: 0
Accepted
time: 19ms
memory: 11684kb

input:

218138 28238

output:

392861201

result:

ok 1 number(s): "392861201"

Test #10:

score: 0
Accepted
time: 27ms
memory: 11560kb

input:

644125 316810

output:

420621854

result:

ok 1 number(s): "420621854"

Test #11:

score: 0
Accepted
time: 29ms
memory: 11660kb

input:

612914 505428

output:

973686286

result:

ok 1 number(s): "973686286"

Test #12:

score: 0
Accepted
time: 12ms
memory: 11628kb

input:

998216 938963

output:

251335926

result:

ok 1 number(s): "251335926"

Test #13:

score: 0
Accepted
time: 12ms
memory: 11524kb

input:

990516 996933

output:

549551960

result:

ok 1 number(s): "549551960"

Test #14:

score: 0
Accepted
time: 52ms
memory: 11684kb

input:

999019 999012

output:

637189128

result:

ok 1 number(s): "637189128"

Test #15:

score: 0
Accepted
time: 45ms
memory: 11652kb

input:

999928 999950

output:

185229465

result:

ok 1 number(s): "185229465"

Test #16:

score: 0
Accepted
time: 13ms
memory: 11520kb

input:

999999 999999

output:

384164916

result:

ok 1 number(s): "384164916"

Test #17:

score: 0
Accepted
time: 46ms
memory: 11592kb

input:

999999 1000000

output:

696165930

result:

ok 1 number(s): "696165930"

Test #18:

score: 0
Accepted
time: 15ms
memory: 11528kb

input:

1000000 999999

output:

219071706

result:

ok 1 number(s): "219071706"

Test #19:

score: 0
Accepted
time: 53ms
memory: 11720kb

input:

1000000 1000000

output:

128206597

result:

ok 1 number(s): "128206597"

Test #20:

score: 0
Accepted
time: 8ms
memory: 11756kb

input:

2 10

output:

1410

result:

ok 1 number(s): "1410"

Test #21:

score: 0
Accepted
time: 11ms
memory: 11664kb

input:

84 16

output:

297627153

result:

ok 1 number(s): "297627153"

Test #22:

score: 0
Accepted
time: 8ms
memory: 11668kb

input:

643 800

output:

489237163

result:

ok 1 number(s): "489237163"

Test #23:

score: 0
Accepted
time: 12ms
memory: 11608kb

input:

9903 880

output:

595167333

result:

ok 1 number(s): "595167333"

Test #24:

score: 0
Accepted
time: 14ms
memory: 11724kb

input:

97446 89750

output:

410205549

result:

ok 1 number(s): "410205549"

Test #25:

score: 0
Accepted
time: 20ms
memory: 11528kb

input:

186460 646474

output:

32638530

result:

ok 1 number(s): "32638530"

Test #26:

score: 0
Accepted
time: 30ms
memory: 11556kb

input:

508940 244684

output:

598321755

result:

ok 1 number(s): "598321755"

Test #27:

score: 0
Accepted
time: 27ms
memory: 11608kb

input:

583646 557758

output:

858695621

result:

ok 1 number(s): "858695621"

Test #28:

score: 0
Accepted
time: 45ms
memory: 11656kb

input:

969610 992608

output:

256683498

result:

ok 1 number(s): "256683498"

Test #29:

score: 0
Accepted
time: 53ms
memory: 11544kb

input:

995106 996434

output:

411791999

result:

ok 1 number(s): "411791999"

Test #30:

score: 0
Accepted
time: 50ms
memory: 11716kb

input:

999961 999872

output:

61222370

result:

ok 1 number(s): "61222370"

Test #31:

score: 0
Accepted
time: 47ms
memory: 11752kb

input:

999977 999908

output:

831096762

result:

ok 1 number(s): "831096762"

Test #32:

score: 0
Accepted
time: 49ms
memory: 11672kb

input:

999992 999998

output:

562977678

result:

ok 1 number(s): "562977678"

Test #33:

score: 0
Accepted
time: 11ms
memory: 11608kb

input:

1000000 2

output:

118436113

result:

ok 1 number(s): "118436113"

Test #34:

score: 0
Accepted
time: 14ms
memory: 11644kb

input:

2 1000000

output:

298823641

result:

ok 1 number(s): "298823641"