Project Euler：Problem 70 Totient permutation

Euler's Totient function, φ(n) [sometimes called the phi function], is used to determine the number of positive numbers less than or equal to n which are relatively prime to n. For example, as 1, 2, 4, 5, 7, and 8, are all less than nine and relatively prime to nine, φ(9)=6.
The number 1 is considered to be relatively prime to every positive number, so φ(1)=1.

Interestingly, φ(87109)=79180, and it can be seen that 87109 is a permutation of 79180.

Find the value of n, 1 < n < 10⁷, for which φ(n) is a permutation of n and the ratio n/φ(n) produces a minimum.

#include <iostream>#include <map>using namespace std;int getEuler(int n){int m = n;int p = 2;int k = 0;while (p*p <= n){k = 0;while (n%p == 0){n /= p;k++;}if (k >= 1)m = m / p*(p - 1);p++;}if (n > 1)m = m / n*(n - 1);return m;}map<int, int> getnum(int n){map<int, int>mp;while (n){mp[n % 10]++;n /= 10;}return mp;}bool isPermutation(int a,int b){map<int, int>an = getnum(a);map<int, int>bn = getnum(b);if (an == bn)return true;elsereturn false;}int main(){double mine = 10000000.0;int num;for (int i = 2; i <= 10000000; i++){int b = getEuler(i);double tmp = i*1.0 / b;if (isPermutation(i,b)){//cout << i << " " << b << endl;if (tmp < mine){mine = tmp;num = i;}}}cout << num << " " << mine << endl;system("pause");return 0;}