Why do I get runtime error during submission even when the code works well in the CodeChef Editor?

My code works well in the CodeChef Editor. Why does it show runtime error (NZEC) after submitting the code?

Link to my code

@rudra09 Look at the case when number A is less then B.
In this Case your GCD function is failing.
for e.g. if you take a=3 and b=5
then at first step b%a will be 2 which will be rem and acc. to your algo for next iteration b=3 and a=2…
In next iteration rem will be 1 and hence b will be 2 and a=1.
And in the final iteration b%a==0 as 1 divides 2 and this will give b=1 and a=0.
And according to your implementation as b still not equal to zero, it will iterate further,so it will again iterate to next step which will give “divide by zero error” as (1%0).
So, Modify your GCD function accordingly or just Swap(a,b) for a<b case.
Further your code will still give WA as the return type and argument type of LCM function should be long as LCM may be larger than 10^9.

Here is the link of successful submission with few modifications stated above:

https://www.codechef.com/viewsolution/18970549

Hope it help!!