SRM 400 DIV2 [500]

#include<iostream>
#include<string>
#include<vector>
#include<set>
#include<algorithm>
#include<memory.h>
#include<cmath>
#include<cstdio>
using namespace std;

long long num;

bool is(int p,int q)
...{
    long long temp=1;
    for (int i=0;i!=q;++i)
        temp*=(long long)p;
    if (temp!=num) return false;
    for (int i=2;i*i<=p;++i)
        if (p%i==0) return false;
    return true;
}

class StrongPrimePower...{
public:
    vector <int> baseAndExponent(string n)
    ...{
        vector<int> ans;
        sscanf(n.c_str(),"%lld",&num);
        double f=num;
        for (int i=2;i!=65;++i)...{
            int p=pow(f,(double)1/i)+0.5;
            if (is(p,i))...{
                ans.push_back(p);
                ans.push_back(i);
                return ans;
            }
        }
        return ans;
    }
};

Problem Statement
	NOTE: This problem statement contains superscripts that may not display properly if viewed outside of the applet. A number which can be represented as pq, where p is a prime number and q is an integer greater than 0, is called a prime power. If q is larger than 1, we call the number a strong prime power. You are given an integer n. If n is a strong prime power, return an vector <int> containing exactly two elements. The first element is p and the second element is q. If n is not a strong prime power, return an empty vector <int>.
Definition
	Class: StrongPrimePower Method: baseAndExponent Parameters: string Returns: vector <int> Method signature: vector <int> baseAndExponent(string n) (be sure your method is public)
Constraints
-	n will contain digits ('0' - '9') only.
-	n will represent an integer between 2 and 10^18, inclusive.
-	n will have no leading zeros.
Examples
0)
	"27" Returns: {3, 3 } 27 = 33. This is a strong prime power.
1)
	"10" Returns: { } 10 = 2 * 5. This is not a strong prime power.
2)
	"7" Returns: { } A prime number is not a strong prime power.
3)
	"1296" Returns: { }
4)
	"576460752303423488" Returns: {2, 59 }
5)
	"999999874000003969" Returns: {999999937, 2 }

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