整数 N! 分解质因数：C++ 代码实现及示例解析

```cpp #include <iostream> #include <vector> using namespace std; int main() { int n; cin >> n; // 使用筛法找出所有质数 vector<bool> is_prime(n + 1, true); vector<int> primes; for (int i = 2; i <= n; i++) { if (is_prime[i]) { primes.push_back(i); for (long long j = (long long)i * i; j <= n; j += i) { is_prime[j] = false; } } } // 对每个质数计算在 n! 中的指数 for (int p : primes) { long long count = 0; long long power = p; while (power <= n) { count += n / power; power *= p; } cout << p << " " << count << endl; } return 0; } ``` ######[AI问答 | 213点数解答 | 2026-01-11 17:51:06]