LeetCode - 715. Range module (TreeSet)*****

TreeSet

class RangeModule {
    
    class Pair{
    
        int left;
        int right;
        public Pair(int left,int right){
    
            this.left = left;
            this.right = right;
        }
    }
    class PairComparator implements Comparator<Pair>{
    
        public int compare(Pair p1,Pair p2){
    
            if(p1.right == p2.right)
               return p1.left - p2.left;
            else
              return p1.right - p2.right;
        }
    }
    private TreeSet<Pair> set;
    public RangeModule() {
    
        set = new TreeSet<>(new PairComparator());
    }
    
    public void addRange(int left, int right) {
    
        //tailSet(E fromElement)： return >=fromElement Set element of value 
       Iterator<Pair> itr = set.tailSet(new Pair(0,left)).iterator();
       while(itr.hasNext()){
    
           Pair pair = itr.next();
           if(right < pair.left)
             break;
           left = Math.min(left,pair.left);
           right = Math.max(right,pair.right);
           itr.remove();
       }
       set.add(new Pair(left,right));
    }
    
    public boolean queryRange(int left, int right) {
    
           //public E higher(E e)： Returns the minimum key value that is strictly greater than the given key value 
           Pair pair = set.higher(new Pair(0,left));
           return (pair != null && pair.left <= left && right <= pair.right);
    }
    
    public void removeRange(int left, int right) {
    
         Iterator<Pair> itr = set.tailSet(new Pair(0,left)).iterator();
         ArrayList<Pair> todo = new ArrayList();
         while(itr.hasNext()){
    
             Pair pair = itr.next();
             if(right < pair.left)
                break;
             if(left  > pair.left) todo.add(new Pair(pair.left,left));
             if(right < pair.right) todo.add(new Pair(right,pair.right));
             itr.remove();
         }
         for(Pair pair: todo) set.add(pair);
    }
}

/** * Your RangeModule object will be instantiated and called as such: * RangeModule obj = new RangeModule(); * obj.addRange(left,right); * boolean param_2 = obj.queryRange(left,right); * obj.removeRange(left,right); */