These two loops for can be executed separately?

In terms of calculation speed, it is the same:

for(int a = 0; a<10; a++)
{
  var1[a] = random(255);
}

for(int b = 0; b<10; b++)
{
  var2[b] = random(255);
}

a:

for(int a = 0; a<10; a++)
{
  var1[a] = random(255);
  var2[a] = random(255);
}

Because from the ignorance and my common sense, despite being two cycles (hence, 20 searches in the arrays) in the first case, in the 2nd it changes its value to twice as many variables as in the first.

Thank you very much