[蓝桥杯]分解质因数

穷举所有质因子，穷举法

 #include<iostream>
using namespace std;
bool isprime(int n)
{
	for (int i = 2; i <= n / i; i++)
	{
		if (n % i == 0)
		{
		    return false;
		   
		}
	}
	return true;
}
int main(int argc, char const* argv[])
{
	int a, b;
	cin >> a >> b;
	for (int k = a; k <= b; k++)
	{
	    int i=k;
		if (isprime(i))
			cout << i << "=" << i << endl;
		else
		{
			int temp = 0;
			cout << i << "=";
			for (int j = 2; j <=  i/j ; j++)
			{
				if (i % j == 0)
				{
				    while(i%j==0)
				    {
					i = i / j;
					if (!temp)
					{
						cout << j;
						temp = 1;
					}
					else
						cout << "*" << j;
				    }
				}
			}
			if (i > 1)
				cout << "*" << i << endl;
		    else
		    cout<<endl;
		}

	}
	return 0;
}