Question

This problem drives me crazy.I have vectorA(float),vectorB(string1),vectorC(string2) which are parallel and i want to eliminate the duplicates in vectorA ,while i manage to retain the
parallelity among the vectors.
Any ideas?

Answer 1

Create a set<float> for items that you have seen, scan through vectorA recording duplicate indexes, then delete indexes that you marked as duplicates while going back starting at the end of the vectors.

Set<Float> seen = new HashSet<Float>();
List<Integer> del = new List<Integer>();
for (int i = 0 ; i != vectorA.size() ; i++) {
    if (seen.add(vectorA[i])) {
        del.add(i);
    }
}
for (int i = del.size()-1 ; i >= 0 ; i--) {
    vectorA.remove(del[i]);
    vectorB.remove(del[i]);
    vectorC.remove(del[i]);
}

Going back is important, because otherwise your indexes will get out of sync.