## Compressing Posting List using Simple-9 algorithm:

**Description:** This algorithm works by checking the Δ-values in a posting sequence and tries to squeeze as many of them as possible into a 32 bit machine word. In this 32 bit, 4 bits are reserved for a selector, which tells how many Δ-values of equal size have been inserted in the remaining 28 bits. There are nine different ways of dividing then into chunks of equal size.

**Example:**

Input Word: "The" 1624 1650 1876 1972 2356

Δ-values : 1624 25 225 95 383 [Δ-value: [1650 -1624 -1] = 25, ...]

The above indexes can be saved as 1624 and 25 together as two 14-bits each;
225, 95, and 383 together as three 9-bits each, and one unused bit at the end.