DMPG '16 G6 - SAO Queries

View as PDF

Submit solution

Points: 30 (partial)
Time limit: 3.5s
Memory limit: 768M

Author:
Problem types
Allowed languages
Ada, Assembly, Awk, Brain****, C, C#, C++, COBOL, CommonLisp, D, Dart, F#, Forth, Fortran, Go, Groovy, Haskell, Intercal, Java, JS, Kotlin, Lisp, Lua, Nim, ObjC, OCaml, Octave, Pascal, Perl, PHP, Pike, Prolog, Python, Racket, Ruby, Rust, Scala, Scheme, Sed, Swift, TCL, Text, Turing, VB, Zig

Kirito has an array of size N, indexed from 0 to N-1. There are Q queries he wants you to perform on this array. Each query is a Squared Appearances Online (SAO) query on a subarray of the array. The SAO query is computed as follows: for each element x in the subarray, let count(x) be the number of occurrences of x in the subarray. The result of the SAO query is the sum of count(x) for each x in the subarray when taken modulo 2^{18} (if an element x appears more than once in the array, you should add count(x) for each time it appears in the array).

You may think that this problem is pretty easy so far, but remember the 'O' in SAO query: you should perform these queries in an online manner. To enforce this condition, the input will be encrypted (see the input specification for more details).

Input Specification

The first line of input will contain N and Q.
The second line of input will contain N space separated nonnegative integers, the elements of the array.
The next Q lines of input will each contain a encrypted query pair x\ y: you should decode them by finding l = x \oplus lastAns and r = y \oplus lastAns, where lastAns is the answer to the previous query (or 0 if it's the first query). Then you should output the result of the SAO query on the subarray from l to r inclusive (0-based index). \oplus denotes the bitwise XOR operation. It is guaranteed that l and r will represent a valid subarray after decryption.

Output Specification

For each SAO query, output the result on a new line. Remember that the result should be taken modulo 2^{18} and that lastAns will be equal to exactly the value you printed last (so, it will also be between 0 and 2^{18}-1).

Constraints

For all subtasks,
1 \le N \le 262\,144
1 \le Q \le 262\,144
All other integers in the input will be between 0 and 262\,143, inclusive.

[Subtask 1 - 5%]

1 \le N \le 1\,000
1 \le Q \le 1\,000

[Subtask 2 - 55%]

1 \le N \le 65\,536
1 \le Q \le 65\,536

[Subtask 3 - 40%]

No additional constraints.

Sample Input

5 5
0 1 2 1 2
0 4
9 10
7 5
7 1
6 1

Sample Input (not encrypted)

For your convenience, we provide a version of the sample input that is NOT encrypted. Remember, all of the real test files will be encrypted (like the input above).

5 5
0 1 2 1 2
0 4
0 3
1 3
2 4
3 4

Sample Output

9
6
5
5
2

Comments


  • 1
    Rafbill  commented on May 18, 2016, 3:16 p.m.

    The range is [4,5] but the bounds should be in [0, 4]


    • 2
      FatalEagle  commented on May 18, 2016, 3:45 p.m.

      You are correct, the sample input has been updated. Sorry about that.

      All the queries in the actual judging data are correct, only the sample was incorrect.