SP13365 BOULDER - Move the boulder

A huge boulder is somehow blocking a public square. The citizens, each one of them approaching from his/her street, decide to remove it. Each citizen can try to either push the boulder away from him, pull it towards him, or choose to do nothing. (note that the citizens cannot change their direction relative to the boulder). Obviously, they want to remove the boulder as quickly as possible - in other words, they want to maximise the magnitude of the net force they apply. Tell them what this maximum possible magnitude is.

The first line contains T (1 For each test case, the first line contains N (1 - The first two integers (each - The next two integers F $ _{pull} $ and F $ _{push} $ (1

For each test case, output a single decimal number, correct to 6 digits after the decimal point, representing the maximum possible magnitude of resultant force.