PBDS java (upto N)

class PBDS{
	private int N;	// tot number of Nodes
	
	private int[] bit; // Binary Index Tree
	
	private int tot; // Keep track of number of elements
	
	private TreeSet<Integer> tree;
	private boolean duplicate; // duplicates are Allowed or Not
	
	PBDS(boolean duplicate , int n){
		this.duplicate = duplicate;
		tree = new TreeSet<>();
	
		this.N = (int)(n + 1);
		bit = new int[N];
		this.tot = 0;
	}
	
	// update BIT
	private void update(int ind , int val ) {
		for( ; ind<N  ;ind += (ind & (-ind))) {
			bit[ind] += val;
		}
	}
	
	// PREFIX SUM for given index
	private int val(int ind) {
		int tot = 0;
		while(ind > 0) {
			tot += bit[ind];
			ind -= (ind & (-ind));
		}	
		return tot;
	}
	
	void add(int ele) {
		Integer ind = ele;
		if(ind == null) return;
		if(!duplicate && count(ind) > 0) return;
		update(ind , 1);
		tree.add(ele);
		tot++;
	}
	boolean contains(int ele) {
		Integer ind = ele;
		if(ind == null) return false;
		return count(ind) > 0;
	}
	private int count(int ele) {
		return val(ele) - val(ele - 1);
	}
	boolean remove(int ele) {
		Integer ind = ele;
		if(ind == null) return false;
		if(count(ind) == 0 ) return false;
		if(count(ind) == 1) tree.remove(ele);
		update(ind , -1);
		tot--;
		return true;
	}
	int size() {
		return tot;
	}
	
	Integer eleAtIndex(int index) {
		if(index > tot || index < 1) return null;
		int l = 1 , r = N-1;
		while(l<=r) {
			int m = (l+r)/2;
			if(val(m) < index) l = m+1;
			else r = m-1;
		}
		return l; 
	}
	
	int count_ceil(int ele) {
		int l = 1 , r = N-1;
		
		int ind = ele-1;
		
		int count = val(ind);
		return tot - count;
	}
	
	Integer ceil(int ele) {
		return tree.ceiling(ele);
	}
	
	
	int count_floor(int ele) {
		
		int ind = ele;
		int count = val(ind);
		return count;
	}
	
	Integer floor(int ele) {
		
		return tree.floor(ele);
	}
	void clearAll() {
		while(!tree.isEmpty()) {
			int first = tree.first();
			while(count(first) > 0) this.remove(first);
			tree.remove(first);
		}
	}
	
	public String toString() {
		StringBuilder sb = new StringBuilder();
		for(int i  = 1 ; i<N ; i++) {
			int c = count(i);
			int ele = i;
			while(c -- >0) {
				sb.append(ele +",");
			}
		}
		return String.valueOf(sb);
	}
	
}