Defuse the Bomb

You have a bomb to defuse, and your time is running out! Your informer will provide you with a circular array code  of length of n  and a key k . To decrypt the code, you must replace every number. All the numbers are replaced simultaneously . If k > 0 , replace the i th number with the sum of the next k numbers. If k < 0 , replace the i th number with the sum of the previous k numbers. If k == 0 , replace the i th number with 0 . As code is circular, the next element of code[n-1] is code[0] , and the previous element of code[0] is code[n-1] . Given the circular array code and an integer key k , return the decrypted code to defuse the bomb !