Replace and Keep Sorted

2000ms

262144K

Description:

Given a positive integer $$$k$$$, two arrays are called $$$k$$$-similar if:

they are strictly increasing;
they have the same length;
all their elements are positive integers between $$$1$$$ and $$$k$$$ (inclusive);
they differ in exactly one position.

You are given an integer $$$k$$$, a strictly increasing array $$$a$$$ and $$$q$$$ queries. For each query, you are given two integers $$$l_i \leq r_i$$$. Your task is to find how many arrays $$$b$$$ exist, such that $$$b$$$ is $$$k$$$-similar to array $$$[a_{l_i},a_{l_i+1}\ldots,a_{r_i}]$$$.

Input:

The first line contains three integers $$$n$$$, $$$q$$$ and $$$k$$$ ($$$1\leq n, q \leq 10^5$$$, $$$n\leq k \leq 10^9$$$) — the length of array $$$a$$$, the number of queries and number $$$k$$$.

The second line contains $$$n$$$ integers $$$a_1, a_2, \ldots,a_n$$$ ($$$1 \leq a_i \leq k$$$). This array is strictly increasing — $$$a_1 < a_2 < \ldots < a_n$$$.

Each of the following $$$q$$$ lines contains two integers $$$l_i$$$, $$$r_i$$$ ($$$1 \leq l_i \leq r_i \leq n$$$).

Output:

Print $$$q$$$ lines. The $$$i$$$-th of them should contain the answer to the $$$i$$$-th query.

Sample Input:

Sample Output:

4
3

Sample Input:

6 5 10
2 4 6 7 8 9
1 4
1 2
3 5
1 6
5 5

Sample Output:

Note:

In the first example:

In the first query there are $$$4$$$ arrays that are $$$5$$$-similar to $$$[2,4]$$$: $$$[1,4],[3,4],[2,3],[2,5]$$$.

In the second query there are $$$3$$$ arrays that are $$$5$$$-similar to $$$[4,5]$$$: $$$[1,5],[2,5],[3,5]$$$.

Informação

Provedor Codeforces

Código CF1485B