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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#106728#6417. Classical Summation ProblemhongrockAC ✓143ms19132kbC++171.6kb2023-05-18 22:05:322023-05-18 22:05:34

Judging History

你现在查看的是最新测评结果

  • [2023-08-10 23:21:45]
  • System Update: QOJ starts to keep a history of the judgings of all the submissions.
  • [2023-05-18 22:05:34]
  • 评测
  • 测评结果:AC
  • 用时:143ms
  • 内存:19132kb
  • [2023-05-18 22:05:32]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;

#define rep(i, a, n) for(int i=(a); i<(n); ++i)
#define per(i, a, n) for(int i=(a); i>(n); --i)
#define pb emplace_back
#define mp make_pair
#define clr(a, b) memset(a, b, sizeof(a))
#define all(x) (x).begin(),(x).end()
#define lowbit(x) (x & -x)
#define fi first
#define se second
#define lson o<<1
#define rson o<<1|1
#define gmid l[o]+r[o]>>1
 
using ll = long long;
using ull = unsigned long long;
using pii = pair<int,int>;
using pll = pair<ll, ll>;
using ui = unsigned int;
 
constexpr int mod = 998244353;
constexpr int inf = 0x3f3f3f3f;
constexpr double EPS = 1e-8;
const double PI = acos(-1.0);

constexpr int N = 1e6 + 10;

ll pow_mod(ll x, int p){
  ll s = 1;
  while(p){
    if(p & 1) s = s * x % mod;
    x = x * x % mod;
    p >>= 1;
  }
  return s;
}

int n, k;
ll fac[N], rev[N];

ll C(int n, int m){
  return fac[n] * rev[m] % mod * rev[n - m] % mod;
}

void _main(){
  cin >> n >> k;
  ll e = (1 + n) * pow_mod(2, mod - 2) % mod;
  if(k % 2 == 0){
    fac[0] = 1;
    rep(i, 1, N)  fac[i] = fac[i-1] * i % mod;
    rev[N - 1] = pow_mod(fac[N - 1], mod - 2);
    per(i, N - 1, 0)  rev[i-1] = rev[i] * i % mod;
    ll d = 0;
    rep(i, 1, n){
      d = d + pow_mod(i, k / 2) * pow_mod(n - i, k / 2) % mod;
    }
    d = d % mod * C(k, k / 2) % mod * pow_mod(pow_mod(n, mod - 2), k) % mod;
    d = d * pow_mod(2, mod - 2) % mod;
    e = (e + mod - d) % mod;
  }

  cout << e * pow_mod(n, k) % mod << '\n';
}

int main(){
  ios::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  _main();
  return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 7ms
memory: 19024kb

input:

3 2

output:

14

result:

ok 1 number(s): "14"

Test #2:

score: 0
Accepted
time: 1ms
memory: 3244kb

input:

5 3

output:

375

result:

ok 1 number(s): "375"

Test #3:

score: 0
Accepted
time: 14ms
memory: 18952kb

input:

2 2

output:

5

result:

ok 1 number(s): "5"

Test #4:

score: 0
Accepted
time: 0ms
memory: 3336kb

input:

10 9

output:

508778235

result:

ok 1 number(s): "508778235"

Test #5:

score: 0
Accepted
time: 2ms
memory: 3300kb

input:

69 3

output:

11497815

result:

ok 1 number(s): "11497815"

Test #6:

score: 0
Accepted
time: 2ms
memory: 3520kb

input:

994 515

output:

33689623

result:

ok 1 number(s): "33689623"

Test #7:

score: 0
Accepted
time: 9ms
memory: 19044kb

input:

4476 6182

output:

114894183

result:

ok 1 number(s): "114894183"

Test #8:

score: 0
Accepted
time: 2ms
memory: 3340kb

input:

58957 12755

output:

932388891

result:

ok 1 number(s): "932388891"

Test #9:

score: 0
Accepted
time: 34ms
memory: 19096kb

input:

218138 28238

output:

392861201

result:

ok 1 number(s): "392861201"

Test #10:

score: 0
Accepted
time: 83ms
memory: 19132kb

input:

644125 316810

output:

420621854

result:

ok 1 number(s): "420621854"

Test #11:

score: 0
Accepted
time: 89ms
memory: 19036kb

input:

612914 505428

output:

973686286

result:

ok 1 number(s): "973686286"

Test #12:

score: 0
Accepted
time: 2ms
memory: 3420kb

input:

998216 938963

output:

251335926

result:

ok 1 number(s): "251335926"

Test #13:

score: 0
Accepted
time: 0ms
memory: 3424kb

input:

990516 996933

output:

549551960

result:

ok 1 number(s): "549551960"

Test #14:

score: 0
Accepted
time: 139ms
memory: 18960kb

input:

999019 999012

output:

637189128

result:

ok 1 number(s): "637189128"

Test #15:

score: 0
Accepted
time: 143ms
memory: 18960kb

input:

999928 999950

output:

185229465

result:

ok 1 number(s): "185229465"

Test #16:

score: 0
Accepted
time: 2ms
memory: 3300kb

input:

999999 999999

output:

384164916

result:

ok 1 number(s): "384164916"

Test #17:

score: 0
Accepted
time: 129ms
memory: 19096kb

input:

999999 1000000

output:

696165930

result:

ok 1 number(s): "696165930"

Test #18:

score: 0
Accepted
time: 3ms
memory: 3472kb

input:

1000000 999999

output:

219071706

result:

ok 1 number(s): "219071706"

Test #19:

score: 0
Accepted
time: 132ms
memory: 19040kb

input:

1000000 1000000

output:

128206597

result:

ok 1 number(s): "128206597"

Test #20:

score: 0
Accepted
time: 9ms
memory: 19088kb

input:

2 10

output:

1410

result:

ok 1 number(s): "1410"

Test #21:

score: 0
Accepted
time: 15ms
memory: 18960kb

input:

84 16

output:

297627153

result:

ok 1 number(s): "297627153"

Test #22:

score: 0
Accepted
time: 19ms
memory: 18968kb

input:

643 800

output:

489237163

result:

ok 1 number(s): "489237163"

Test #23:

score: 0
Accepted
time: 9ms
memory: 18968kb

input:

9903 880

output:

595167333

result:

ok 1 number(s): "595167333"

Test #24:

score: 0
Accepted
time: 20ms
memory: 19088kb

input:

97446 89750

output:

410205549

result:

ok 1 number(s): "410205549"

Test #25:

score: 0
Accepted
time: 35ms
memory: 18956kb

input:

186460 646474

output:

32638530

result:

ok 1 number(s): "32638530"

Test #26:

score: 0
Accepted
time: 74ms
memory: 19008kb

input:

508940 244684

output:

598321755

result:

ok 1 number(s): "598321755"

Test #27:

score: 0
Accepted
time: 71ms
memory: 19040kb

input:

583646 557758

output:

858695621

result:

ok 1 number(s): "858695621"

Test #28:

score: 0
Accepted
time: 126ms
memory: 18916kb

input:

969610 992608

output:

256683498

result:

ok 1 number(s): "256683498"

Test #29:

score: 0
Accepted
time: 129ms
memory: 19020kb

input:

995106 996434

output:

411791999

result:

ok 1 number(s): "411791999"

Test #30:

score: 0
Accepted
time: 134ms
memory: 18960kb

input:

999961 999872

output:

61222370

result:

ok 1 number(s): "61222370"

Test #31:

score: 0
Accepted
time: 137ms
memory: 18960kb

input:

999977 999908

output:

831096762

result:

ok 1 number(s): "831096762"

Test #32:

score: 0
Accepted
time: 136ms
memory: 18964kb

input:

999992 999998

output:

562977678

result:

ok 1 number(s): "562977678"

Test #33:

score: 0
Accepted
time: 18ms
memory: 19036kb

input:

1000000 2

output:

118436113

result:

ok 1 number(s): "118436113"

Test #34:

score: 0
Accepted
time: 18ms
memory: 19092kb

input:

2 1000000

output:

298823641

result:

ok 1 number(s): "298823641"