I am reading a txt file having two columns where each element is an integer. I'd like to use the elements in the first column as a key, and the elements in the second column as my value.

I am sharing just a small portion of my data set.

```
0   1
0   2
0   3
0   4
1   2
1   3
1   0

```

```
Scanner scanner = new Scanner(new FileReader(DATADIR+"data.txt"));
TreeMap<Integer, List<Integer>> myMap = new TreeMap<Integer, List<Integer>>();
while (scanner.hasNextLine()) {
  String[] line= scanner.nextLine().split("\t");

}

```

Now, what I need is to have a structure with which when I call 0, I should get <1,2,3,4>.