In Java, using comparator, is it possible to sort elements at the specific positions in a list? If so, how?
Example : the list {1,2,3,4,10,6,7,8}
indices of elements to be sorted {3,4,7}
in descending order, the result would be {1,2,3,10,8,6,7,4}.
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2 Answers
Presumably you know the specific positions beforehand? If so, create a new list comprised of the elements you want to sort, sort the list, and then replace the elements in the original list with your sorted list, one element at a time.
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Would something like this work? You would construct the Comparator with a list of the values and the list of indexes to sort:
private static class MyComparator implements Comparator<Integer>{
private ArrayList<Integer> indexes;
private ArrayList<Integer> vals;
public MyComparator(ArrayList<Integer> indexes, ArrayList<Integer> vals){
this.indexes = indexes;
this.vals = vals;
}
@Override
public int compare(Integer arg0, Integer arg1) {
if(indexes.contains(vals.indexOf(arg0)) && indexes.contains(vals.indexOf(arg1))){
return Integer.compare(arg1, arg0);
}
return 0;
}
}
