26 lines
714 B
C++
26 lines
714 B
C++
|
pair<vector<int>, vector<int>> factcount(int n) {
|
||
|
|
vector<bool> not_prime(n + 1);
|
||
|
|
vector<int> res(n + 1), num(n + 1);
|
||
|
|
vector<int> primes;
|
||
|
|
res[1] = 1;
|
||
|
|
for (int i = 2; i <= n; ++i) {
|
||
|
|
if (not not_prime[i]) {
|
||
|
|
res[i] = 2;
|
||
|
|
num[i] = 1;
|
||
|
|
primes.emplace_back(i);
|
||
|
|
}
|
||
|
|
for (auto&& x : primes) {
|
||
|
|
if (i * x > n) break;
|
||
|
|
not_prime[i * x] = 1;
|
||
|
|
if (i % x == 0) {
|
||
|
|
num[i * x] = num[i] + 1;
|
||
|
|
res[i * x] = res[i] / num[i * x] * (num[i * x] + 1);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
num[i * x] = 1;
|
||
|
|
res[i * x] = res[i] * 2;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return {primes, res};
|
||
|
|
}
|