Thread: efficient way of checking duplicates

hi, i was wondering if someone could give me an efficient way of checking and removing duplicates.

basically i have this giant file which parses for IDs and Groups Num.

The condition is that I can have 2 different IDs go into the same group number, but I cannot have 2 of the same IDs (think of it more as repeated) go into the same group.

ie.

ID Group Num
150 200
180 200

would be valid

or

ID Group Num
150 200
150 201

but

ID Group Num
150 200
150 200

would not be.

thanks so much = )

Use a Set, a Map, or combination of the two. In this case, a simple Map keyed with GroupNum and valued with a Set (filled with IDs) would work.