Cheerio Contest 2 P5 - Subsequence Queries
View as PDFGiven an array  of 
 integers, support 
 queries of the following type:
l rreturn the number of subsequences between indexltor(inclusive) which have an even sum.
As the results of these queries may be extremely large, output them modulo .
A subsequence can be created from  by deleting some elements (possibly none, but not all). Two subsequences are different if one contains an index from the original array that the other does not have.
Constraints
For all subtasks:
| Points Awarded | Additional Constraints | 
|---|---|
| 3 points | All  | 
| 5 points | |
| 7 points | No further constraints | 
Input Specification
The first line contains two space-separated integers  and 
.
The next line contains  space-separated integers — the array 
.
The next  lines each contain two space-separated integers 
, and 
, denoting the 
 query.
Output Specification
Output the answer to each query in order on separate lines.
Sample Input
6 1
4 3 1 2 5 7
2 4
Sample Output
3
Comments