Making a tree from two column csv file in java

manpreet Best Answer 2 years ago

I want to have ids and count of all the child of a node using two-column CSV file in which one column is parent id and one is child id.

For e.g

Child Id   Parent Id
C1         C2
C3         C1
C4         C3

I want result like this:

C2  C1, C3, C4 3

manpreet 2 years ago

class Child {
List<String> ids;
int count;

    public Child(String id) {
        count=1;
        if (ids.size() < 1) {
            ids = new ArrayList<>();
        }
        ids.add(id);
    }

        public Child setChild(String id) {
        if (ids.size() < 1) {
            ids = new ArrayList<>();
        }
        ids.add(id);
        count++;
        return this;
    }

class Main{

//your logic
Map<String, Child> map = new HashMap<>();
    if (!map.containsKey(parent)){
        map.put(parent,new Child(id));
    }else
    map.computeIfPresent(parent, (key, value) -> value.setChild(id));
}