public Pair getCrossoverPoints(int delta){
		Pair pair = new Pair();
		int len = this.bins.size();

		if(len == 0)
			return null;
		
		pair.x = randRange(0, len - 1);
		
		if(pair.x == (len - 1 )){
			pair.y = len;
		} else {
			pair.y = randRange(pair.x, pair.x + delta); 
		}
		
		return pair;
	}