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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#575395 | #8761. 另一个计数问题 | caojc | WA | 38ms | 5728kb | C++20 | 3.8kb | 2024-09-19 13:43:41 | 2024-09-19 13:43:41 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define db(args...) { \
string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); \
stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); cout << '\n';}
void err(istream_iterator<string> it){}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
cout << *it << " = " << a << ' ';
err(++it, args...);
}
const int mod = 998244353;
ll ksm(ll a, ll b = mod - 2) {
ll res = 1;
while (b) {
if (b & 1) res = res * a % mod;
a = a * a % mod, b /= 2;
}
return res;
}
ll i2, i6;
ll s1(ll n) {
return (1 + n) * n % mod * i2 % mod;
}
ll s1(ll l, ll r) {
return (s1(r) - s1(l - 1) + mod) % mod;
}
ll s2(ll n) {
return n * (n + 1) % mod * (2 * n + 1) % mod * i6 % mod;
}
ll s2(ll l, ll r) {
return (s2(r) - s2(l - 1) + mod) % mod;
}
/*
min25筛第一部分,求质数的多项式和。
*/
vector<int> visi, pri; int cpri;
void init(int N) {
N++; cpri = 0;
visi.assign(N, 0), pri.assign(N, 0);
for (int i = 2; i < N; i++) {
if (!visi[i]) {
visi[i] = i;
pri[++cpri] = i;
}
for (int j = 1; j <= cpri; j++) {
int id = pri[j] * i;
if (id >= N) break;
visi[id] = pri[j];
if (i % pri[j] == 0) break;
}
}
}
struct min25 {
// 幂次k=1
ll sn, n;
vector<int> id;
vector<ll> g;
int getid(ll x) {
if (x <= sn) return x;
return id[n / x];
}
min25(ll N, int k) {
n = N;
sn = sqrt((long double)n);
init(2 * sn + 10); // todo
id.assign(sn + 1, 0);
g.assign(sn * 2 + 1, 0);
vector<ll> big(sn * 2 + 1), G(sn + 1);
for (int i = 2; i <= sn; i++) {
G[i] = G[i - 1] + (visi[i] == i) * ksm(i, k);
g[i] %= mod;
}
for (int i = 1; i <= sn; i++) {
id[i] = 2 * sn + 1 - i;
big[i] = i, big[id[i]] = n / i;
}
for (int i = 1; i <= sn * 2; i++) {
if (k == 0) g[i] = big[i] - 1; // todo 除了1所有数的k次方前缀和
if (k == 1) g[i] = (s1(big[i]) - 1 + mod) % mod;
if (k == 2) g[i] = (s2(big[i]) - 1 + mod) % mod;
}
for (int j = 1, beg = 1; pri[j] <= sn; j++) {
while (j > 1 && beg <= sn * 2 && pri[j] * 1ll * pri[j] > big[beg]) beg++;
for (int i = sn * 2; i >= beg; i--) {
ll v = ksm(pri[j], k); // todo pri[j] ^ k
g[i] = g[i] - v * (g[getid(big[i] / pri[j])] - G[pri[j - 1]]);
g[i] = (g[i] % mod + mod) % mod;
}
}
}
ll get(ll n) {
return g[getid(n)];
}
};
void solve() {
i2 = ksm(2), i6 = ksm(6);
ll n;
cin >> n;
ll ans1 = 0;
ans1 = (s1(2, n / 2) * s1(2, n / 2) % mod - s2(2, n / 2) + mod) % mod * i2 % mod;
min25 m1(n, 1);
min25 m2(n, 2);
ll v1 = s1(2, n / 2), v2 = (s1(n / 2 + 1, n) - (m1.get(n) - m1.get(n / 2)));
v2 = (v2 % mod + mod) % mod;
ll ans2 = v1 * v2;
ans2 = (ans2 % mod + mod) % mod;
ll v = s1(n / 2 + 1, n) - (m1.get(n) - m1.get(n / 2));
v = (v % mod + mod) % mod;
ll ans3 = (v * v - (s2(n / 2 + 1, n) - m2.get(n) + m2.get(n / 2)));
ans3 = (ans3 % mod + mod) % mod;
ans3 = ans3 * i2 % mod;
ll ans = ans1 + ans2 + ans3;
ans = (ans % mod + mod) % mod;
cout << ans << '\n';
}
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
int t = 1;
// cin >> t;
while (t--) solve();
return 0;
}
/*
g++ 1.cpp -std=c++20 -o 1 && ./1 < in.txt > out.txt
*/
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 3576kb
input:
4
output:
8
result:
ok 1 number(s): "8"
Test #2:
score: 0
Accepted
time: 0ms
memory: 3640kb
input:
5
output:
8
result:
ok 1 number(s): "8"
Test #3:
score: 0
Accepted
time: 0ms
memory: 3524kb
input:
6
output:
80
result:
ok 1 number(s): "80"
Test #4:
score: 0
Accepted
time: 0ms
memory: 3612kb
input:
7
output:
80
result:
ok 1 number(s): "80"
Test #5:
score: 0
Accepted
time: 0ms
memory: 3788kb
input:
8
output:
200
result:
ok 1 number(s): "200"
Test #6:
score: 0
Accepted
time: 0ms
memory: 3644kb
input:
9
output:
407
result:
ok 1 number(s): "407"
Test #7:
score: 0
Accepted
time: 0ms
memory: 3576kb
input:
10
output:
937
result:
ok 1 number(s): "937"
Test #8:
score: 0
Accepted
time: 0ms
memory: 3640kb
input:
79
output:
3224298
result:
ok 1 number(s): "3224298"
Test #9:
score: 0
Accepted
time: 0ms
memory: 3652kb
input:
123
output:
21077222
result:
ok 1 number(s): "21077222"
Test #10:
score: 0
Accepted
time: 0ms
memory: 3664kb
input:
158
output:
57411585
result:
ok 1 number(s): "57411585"
Test #11:
score: 0
Accepted
time: 0ms
memory: 3792kb
input:
285
output:
605750829
result:
ok 1 number(s): "605750829"
Test #12:
score: 0
Accepted
time: 0ms
memory: 3656kb
input:
355
output:
509863120
result:
ok 1 number(s): "509863120"
Test #13:
score: 0
Accepted
time: 0ms
memory: 3728kb
input:
484
output:
311440260
result:
ok 1 number(s): "311440260"
Test #14:
score: 0
Accepted
time: 0ms
memory: 3576kb
input:
520
output:
102191845
result:
ok 1 number(s): "102191845"
Test #15:
score: 0
Accepted
time: 0ms
memory: 3656kb
input:
706
output:
300787918
result:
ok 1 number(s): "300787918"
Test #16:
score: 0
Accepted
time: 0ms
memory: 3548kb
input:
747
output:
505062591
result:
ok 1 number(s): "505062591"
Test #17:
score: 0
Accepted
time: 0ms
memory: 3656kb
input:
784
output:
181810798
result:
ok 1 number(s): "181810798"
Test #18:
score: 0
Accepted
time: 0ms
memory: 3532kb
input:
76879
output:
716166793
result:
ok 1 number(s): "716166793"
Test #19:
score: 0
Accepted
time: 0ms
memory: 3632kb
input:
209295
output:
753032272
result:
ok 1 number(s): "753032272"
Test #20:
score: 0
Accepted
time: 0ms
memory: 3564kb
input:
220895
output:
874612082
result:
ok 1 number(s): "874612082"
Test #21:
score: 0
Accepted
time: 0ms
memory: 3556kb
input:
243390
output:
68635874
result:
ok 1 number(s): "68635874"
Test #22:
score: 0
Accepted
time: 1ms
memory: 3688kb
input:
414767
output:
862578797
result:
ok 1 number(s): "862578797"
Test #23:
score: 0
Accepted
time: 1ms
memory: 3604kb
input:
431662
output:
231728766
result:
ok 1 number(s): "231728766"
Test #24:
score: 0
Accepted
time: 0ms
memory: 3692kb
input:
521130
output:
106207351
result:
ok 1 number(s): "106207351"
Test #25:
score: 0
Accepted
time: 1ms
memory: 3728kb
input:
668419
output:
580625063
result:
ok 1 number(s): "580625063"
Test #26:
score: 0
Accepted
time: 1ms
memory: 3660kb
input:
700378
output:
790849562
result:
ok 1 number(s): "790849562"
Test #27:
score: 0
Accepted
time: 1ms
memory: 3716kb
input:
965876
output:
856082142
result:
ok 1 number(s): "856082142"
Test #28:
score: -100
Wrong Answer
time: 38ms
memory: 5728kb
input:
998244350
output:
661423330
result:
wrong answer 1st numbers differ - expected: '539142456', found: '661423330'