QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#106728 | #6417. Classical Summation Problem | hongrock | AC ✓ | 143ms | 19132kb | C++17 | 1.6kb | 2023-05-18 22:05:32 | 2023-05-18 22:05:34 |
Judging History
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"