Topcoder SRM 668 DIV 2

VerySecureEncryption 模拟

题意：

题解：

代码：

#include<iostream>
#include<map>
#include<algorithm>
using namespace std;

typedef long long ll;

int ma[1000006];

ll gcd(ll a,ll b) {
return b == 0 ? a : gcd(b, a % b);
}

class AnArray {
public:
int solveProblem(vector<int> A, int K) {
for (auto a:A) {
for (int i = 1; i * i <= a; i++) {
if (a % i == 0) {
ma[i]++;
int t = a / i;
if (i * i != a && t <= 1000000)ma[t]++;
}
}
}
ll res = 0;
for (int i = 0; i < A.size(); i++)
for (int j = 0; j < A.size(); j++) {
if (i == j)continue;
ll tmp = 1;
tmp = tmp * A[i] * A[j];
int g = gcd(tmp, K);
int t = K / g;
res = res + ma[K / g];
if (A[i] % t == 0)res--;
if (A[j] % t == 0)res--;
}
return res / 6;
}
};