Coding challenge

Bomb Diffusion.java

/*Defuse Bomb
During the war, the enemy battalion has planted a bomb in your bunker. Your informer has sent you a message of the enemy which contains a list having N numbers and key(K) . The numbers have to be used to construct a sequence to diffuse the bomb. According to your informer, the logic to extract the sequence from the whole message is to replace each number with the sum of the next k elements , if the value of k is positive. When the value of K is negative, the number replaced by the sum of previous K numbers. The series of numbers is considered in a cyclic fashion for the last K numbers
Write an algorithm that finds the sequence to defuse the bomb
Input Format
Input to the function consist of three arguments
size , no of elements in the sequence
key , represents the K value
message, represents the sequence
Constraints
0<= size <= 10^5
-10^6 <= message[i] <= 10^6
0<= i <= size
Output Format
Return an array of integers representing the sequence to diffuse the bomb
Sample Input 0
4 3 
4 2 -5 11
Sample Output 0
8 10 17 1*/ 

public void foo(int n. int key, int arr[]){
    int c = key,sum = 0,b = 0;
    for(int i = 0; i < n; i++){
        b = i;
        c = key;
        sum = 0;
        if(key > 0){
            while(c > 0){
                sum += a[(b+1) % n];
                b++;
                c--;
            }
        }
        else{
            while(c < 0){
                if(b <= 0){
                    b = b+n;
                }
                sum += a[(b - 1)];
                b--;
                c++;
            }
        }
        System.out.print(sum + " ");
    }
}

Time complexity: O(n*key)
Space complexity: O(n)