Quadratic probing: In the above case when the first insertion is made the probability of latest element being inserted in a certain position is 1/n where n is the size of the array. At the time of minute insertion the probability becomes 2/n and so on for the kth insertion the probability is k/n, which is k times as compared to any other lasting unoccupied position. Therefore to overcome the phenomenon of long sequence of occupied positions to happen to even longer we use quadratic rehash, in this method if there is a collision at hash address h, this method probes the array at locations h+1, h+4, h+9, ... That is (h(key) +i2 % hash size) for i=1,2,... gives the ith hash of h