10489: ABC105 —— D - Candy Distribution
[Creator : ]
Description
There are $N$ boxes arranged in a row from left to right. The $i$-th box from the left contains $A_i$ candies.
You will take out the candies from some consecutive boxes and distribute them evenly to $M$ children.
Such being the case, find the number of the pairs $(l, r)$ that satisfy the following:
- $l$ and $r$ are both integers and satisfy $1 \leq l \leq r \leq N$.
- $A_l + A_{l+1} + ... + A_r$ is a multiple of $M$.
You will take out the candies from some consecutive boxes and distribute them evenly to $M$ children.
Such being the case, find the number of the pairs $(l, r)$ that satisfy the following:
- $l$ and $r$ are both integers and satisfy $1 \leq l \leq r \leq N$.
- $A_l + A_{l+1} + ... + A_r$ is a multiple of $M$.
Input
Input is given from Standard Input in the following format:
```
$N$ $M$
$A_1$ $A_2$ $...$ $A_N$
```
```
$N$ $M$
$A_1$ $A_2$ $...$ $A_N$
```
Output
Print the number of the pairs $(l, r)$ that satisfy the conditions.
Note that the number may not fit into a $32$-bit integer type.
Note that the number may not fit into a $32$-bit integer type.
Constraints
- All values in input are integers.
- $1 \leq N \leq 10^5$
- $2 \leq M \leq 10^9$
- $1 \leq A_i \leq 10^9$
- $1 \leq N \leq 10^5$
- $2 \leq M \leq 10^9$
- $1 \leq A_i \leq 10^9$
Sample 1 Input
3 2
4 1 5
Sample 1 Output
3
The sum $A_l+A_{l+1}+...+A_r$ for each pair $(l,r)$ is as follows:
- Sum for (1,1): 4
- Sum for (1,2): 5
- Sum for (1,3): 10
- Sum for (2,2): 1
- Sum for (2,3): 6
- Sum for (3,3): 5
Among these, three are multiples of 2.
Sample 2 Input
13 17
29 7 5 7 9 51 7 13 8 55 42 9 81
Sample 2 Output
6
Sample 3 Input
10 400000000
1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000
Sample 3 Output
25