102002: [AtCoder]ABC200 C - Ringo's Favorite Numbers 2
Memory Limit:256 MB
Time Limit:2 S
Judge Style:Text Compare
Creator:
Submit:2
Solved:0
Description
Score : $300$ points
Problem Statement
Ringo loves the integer $200$. Solve the problem below for him.
Given a sequence $A$ of $N$ positive integers, find the pair of integers $(i, j)$ satisfying all of the following conditions:
- $1 \le i < j \le N$;
- $A_i - A_j$ is a multiple of $200$.
Constraints
- All values in input are integers.
- $2 \le N \le 2 \times 10^5$
- $1 \le A_i \le 10^9$
Input
Input is given from Standard Input in the following format:
$N$ $A_1$ $A_2$ $\dots$ $A_N$
Output
Print the answer as an integer.
Sample Input 1
6 123 223 123 523 200 2000
Sample Output 1
4
For example, for $(i, j) = (1, 3)$, $A_1 - A_3 = 0$ is a multiple of $200$.
We have four pairs satisfying the conditions: $(i,j)=(1,3),(1,4),(3,4),(5,6)$.
Sample Input 2
5 1 2 3 4 5
Sample Output 2
0
There may be no pair satisfying the conditions.
Sample Input 3
8 199 100 200 400 300 500 600 200
Sample Output 3
9