How to fix Run-Error issue?

Question

The online Judge in my school says that my code has a run-error issue, even though the input and output of the code are already correct. How do i fix this?

Sample Input :
3
5
1 2 3 4 5
4
4 4 4 4
3
10 1 2

Sample output :
Case #1: 9
Case #2: 8
Case #3: 12

My code :

#include<stdio.h>
int main(){
int t;
long int n = 0, max1, max2, v[100];

scanf("%d", &t);

for(int i=1; i<=t; i++){
if(t>=1 && t<=10){
scanf("%ld", &n);
}

if(n>=2 && n<=1000000){
for(long int j=0; j<n; j++){
scanf("%ld", &v[j]);
}

if (v[0] > v[1])
{
max1 = v[0];
max2 = v[1];
}
else
{
max1 = v[0];
max2 = v[1];
}

for(long int j=2; j<n; j++)
{
if (v[j] > max1)
{
max2 = max1;
max1 = v[j];
}
else if (v[j] > max2)
{
max2 = v[j];
}
}

long int sum=max1+max2;
printf("Case #%d: ", i);
printf("%ld\n", sum);
}

}
return 0;

}

Thank you in advance!

Answer 1

Input and output is sometimes a bottleneck in the program. The following lines
at the beginning of the code make input and output more efficient:

ios::sync_with_stdio(0);
cin.tie(0);

For more clear explanation-

https://stackoverflow.com/questions/31162367/significance-of-ios-basesync-with-stdiofalse-cin-tienull

Answer 2

@EnCoDeR Thank you very much!