- 题解
看题解猜题目
- @ 2026-7-7 17:04:18
提示:是玄武纪oj上的题目
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e6 + 10, mod = 1e9 + 7;
int n, primes[N], cnt;
bool st[N];
void gp(int n) {
for (int i = 2; i <= n; i++) {
if (!st[i]) primes[cnt++] = i;
for (int j = 0; primes[j] * i <= n; j++) {
st[primes[j] * i] = true;
if (i % primes[j] == 0) break;
}
}
}
int main() {
cin >> n;
gp(n);
ll res = 1;
for (int i = 0; i < cnt; i++) {
int p = primes[i];
if (p == 0) continue;
int s = 0;
for (int j = n; j > 0; j /= p) s += j / p;
res = (ll)(2 * s + 1) * res % mod;
}
cout << res << endl;
return 0;
}
据说只有1/7244的玄武纪oj用户能够猜对! 答案在这里.