How to match 2 arrays and get an output in new array Ruby

Let’s say i have 2 arrays with the same length filled with integers

a = (6,3,5,1)
b = (6,2,5,3)

And i want to compare these arrays and get an output in new (c) array so it would look like this

c = (+,-,+,-)

If there will be 0 matches then my new array would give (-,-,-,-) and vice versa in case of 4 matches (+,+,+,+)