Linear probing: inserting a key

• When inserting a key K in a table of size M, with hash function H(K)
  
  1. Set indx = H(K)
  2. If table location indx already contains the key, no need to insert it. Done!
  3. Else if table location indx is empty, insert key there. Done!
  4. Else collision. Set indx = (indx + 1) mod M.
  5. If indx == H(K), table is full! (Throw an exception, or enlarge table.) Else go to 2.
  
  
• So, linear probing basically does a linear search for an empty slot when there is a collision
  
  
• Advantages: easy to implement; always finds a location if there is one; very good average-case performance when the table is not very full
  
  
• Disadvantages: “clusters” or "clumps" of keys form in adjacent slots in the table; when these clusters fill most of the array, performance deteriorates badly as the probe sequence performs what is essentially an exhaustive search of most of the array