链接：
https://codeforces.com/contest/1247/problem/D
题意：
You are given n positive integers a1,…,an, and an integer k≥2. Count the number of pairs i,j such that 1≤i<j≤n, and there exists an integer x such that ai⋅aj=xk.
思路：
对每个数质数拆分，记录质数的指数modk的值，map记录vector神仙操作。。。
代码：
//#include <iostream>
//#include <fstream>
//#include <process.h>
//#include "ch08/ch08Func.cpp"
#include <bits/stdc++.h>
typedef long long LL;
using namespace std;
int n, k;
map<vector<pair<int, int>>, int> Mp;
int main()
{
ios::sync_with_stdio(false);
LL res = 0;
int val;
cin >> n >> k;
for (int i = 1;i <= n;i++)
{
vector<pair<int, int> > v1, v2;
cin >> val;
for (int j = 2;j*j <= val;j++)
{
int _ = 0;
if (val%j == 0)
{
while (val%j == 0)
{
val /= j;
_++;
}
}
if (_%k)
v1.emplace_back(j, _%k);
}
if (val > 1)
v1.emplace_back(val, 1);
for (auto v: v1)
v2.emplace_back(v.first, k-v.second);
res += Mp[v2];
Mp[v1]++;
}
cout << res << endl;
return 0;
}