1652. 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 ith number with the sum of the next k numbers.
• If k < 0, replace the ith number with the sum of the previous k numbers.
• If k == 0, replace the ith 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!

class Solution {
public:
    vector<int> decrypt(vector<int>& code, int k) {
        int n = code.size();
        vector<int> res;
        for(int i = 0; i < n; i++) {
            int now = 0;
            if(k > 0) {
                for(int j = 0; j < k; j++) now = (now + code[(1+i+j)%n]);
            } else if(k < 0) {
                for(int j = 0; j < -k; j++) now = (now + code[(i-j-1+n)%n]);
            }
            res.push_back(now);
        }
        return res;
    }
};