Explain two hash functions.
Division-Method
- In this method we use modular arithmetic system to divide the key value by some integer divisor m (may be table size).
- It gives us the location value, where the element can be placed.
- We can write, L = (K mod m) + 1,
- L = location in table/file
- K = key value
- m = table size/number of slots in file
- Suppose, k = 23, m = 10 then
- L = (23 mod 10) + 1= 3 + 1=4
- The key whose value is 23 is placed in 4th location.
Midsquare Methods
- In this case, we square the value of a key and take the number of digits required to form an address, from the middle position of squared value.
- Suppose a key value is 16
- Its square is 256
- Now if we want address of two digits
- We select the address as 56 (i.e. two digits starting from middle of 256)
