最小公倍數--結果超出int表示範圍

寫代碼時，要注意各種數據類型表示的範圍，求最小公倍數，如果求的數值比較大時，就要注意超出表示範圍的可能，數據開大一點。

//WA
#include<iostream>
using namespace std;

long long GCD1(long long, long long);
long long GCD2(long long, long long);
long long LCM(long long, long long);

int main()
{
	long long n;
	long long m;
	long long val1;
	long long re;

	cin>>n;
	while(n--)
	{
		cin>>m;
		re = 1;
		while(m--)
		{
			cin>>val1;
			re = LCM(re,val1);
		}	
		cout<<re<<endl;
	}
	return 0;
}

long long LCM(long long m, long long n)
{
	return m*n/GCD2(m,n); 
}

long long GCD1(long long m, long long n)
{
	long long val;
	if(m >= n)
	{
		val = m % n;
		if(val == 0)
		{
			return n;
		}
		m = n;
		n = val;
	}
	else
	{
		val = n % m;
		if(val == 0)
		{
			return m;
		}
		n = m;
		m = val;
	}
	//這裏一定要寫return 忘記了return就會報錯的 
	return GCD1(m, n);	
}

long long GCD2(long long m, long long n)
{
	long long val;
	do
	{
		if(m >= n)
		{
			val = m % n;
			//記錄下更小的n 
			m = n;
		}
		else
		{
			val = n % m;
		}
		n = val;
	}while(val != 0);
	return m;
}