模板
#define LOCAL
#include<stdio.h>
int main()
{
#ifdef LOCAL
freopen("H://dataIn.txt", "r", stdin);
freopen("H://dataOut.txt", "w", stdout);
#endif
return 0;
}
GCD代碼
int gcd(int x,int y)
{
if(y==0)return x;
return gcd(y,x%y);
}
歐拉函數:http://blog.csdn.net/mbxc816/article/details/7214872
習題:2.1.6