Problem:
Score : 300 points

Problem Statement

You are given integers N and K. Find the number of triples (a,b,c) of positive integers not greater than N such that a+b,b+c and c+a are all multiples of K.
The order of a,b,c does matter, and some of them can be the same.

Constraints

1 \leq N,K \leq 2\times 10^5

N and K are integers.

Input

Input is given from Standard Input in the following format:

N K

Output

Print the number of triples (a,b,c) of positive integers not greater than N such that a+b,b+c and c+a are all multiples of K.

Sample Input 1

3 2

Sample Output 1

9

(1,1,1),(1,1,3),(1,3,1),(1,3,3),(2,2,2),(3,1,1),(3,1,3),(3,3,1) and (3,3,3) satisfy the condition.

Sample Input 2

5 3

Sample Output 2

1

Sample Input 3

31415 9265

Sample Output 3

27

Sample Input 4

35897 932

Sample Output 4

114191

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
 
public class Main{
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in); 

        int N = sc.nextInt();
        int K = sc.nextInt();
        sc.close();
        int count_1 = 0;
        int count_2 = 0;
        if(K == 2){
            for(int i = 1; i <= N; i = i+2)
                count_1++;
            for(int i = 2; i <= N; i = i+2)
                count_2++;
            System.out.println((int)(Math.pow(count_1, 3) + Math.pow(count_2, 3)));
        } else {
            if(K%2 == 1){
                if(N < K){
                    System.out.println(0);
                } else {
                    for(int i = K; i <= N; i = i + K){
                        count_1++;
                    }
                    System.out.println((int)Math.pow(count_1, 3));
                }
            } else{
                for(int i = K/2; i <= N; i = i + K){
                    count_1++;
                }
                for(int i = K; i <= N; i = i+K){
                    count_2++;
                }
                System.out.println((int)(Math.pow(count_1, 3)+Math.pow(count_2, 3)));
            }
        }
    }
}