python/TangDou/LuoGuBook/P1403_Prepare_2.cpp

#include <bits/stdc++.h>

using namespace std;
typedef long long LL;

/**
 * 功能：计算约数之和
 * @param n
 * @return
 */
LL getSumOfDivisors(LL x) {
    //拆出所有质数因子及质数因子个数
    unordered_map<int, int> primes;
    for (int i = 2; i <= x / i; i++)
        while (x % i == 0) {
            x /= i;
            primes[i]++;
        }
    if (x > 1) primes[x]++;

    //计算约数个数
    LL res = 1;
    for (auto p : primes) {
        LL a = p.first, b = p.second;
        LL t = 1;
        while (b--) t = (t * a + 1);
        res = res * t;
    }
    return res;
}

LL res;

int main() {
    //测试用例：180
    //参考答案：546
    int n;
    cin >> n;
    cout<<getSumOfDivisors(n) << endl;
    return 0;
}