Formatted question description: https://leetcode.ca/all/1652.html

# 1652. Defuse the Bomb

## Level

Easy

## Description

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*!

**Example 1:**

**Input:** code = [5,7,1,4], k = 3

**Output:** [12,10,16,13]

**Explanation:** Each number is replaced by the sum of the next 3 numbers. The decrypted code is [7+1+4, 1+4+5, 4+5+7, 5+7+1]. Notice that the numbers wrap around.

**Example 2:**

**Input:** code = [1,2,3,4], k = 0

**Output:** [0,0,0,0]

**Explanation:** When k is zero, the numbers are replaced by 0.

**Example 3:**

**Input:** code = [2,4,9,3], k = -2

**Output:** [12,5,6,13]

**Explanation:** The decrypted code is [3+9, 2+3, 4+2, 9+4]. Notice that the numbers wrap around again. If k is negative, the sum is of the previous numbers.

**Constraints:**

`n == code.length`

`1 <= n <= 100`

`1 <= code[i] <= 100`

`-(n - 1) <= k <= n - 1`

## Solution

First, obtain `code`

’s length. Then, if `k == 0`

, return an array of all zeros with `code`

’s length. Otherwise, calculate each element in the decrypted array and return the decrypted array.

```
class Solution {
public int[] decrypt(int[] code, int k) {
int length = code.length;
int[] decrypted = new int[length];
if (k == 0)
return decrypted;
for (int i = 0; i < length; i++)
decrypted[i] = getSum(code, i, k);
return decrypted;
}
public int getSum(int[] code, int index, int k) {
int sum = 0;
int length = code.length;
int direction = k > 0 ? 1 : -1;
k = Math.abs(k);
for (int i = 1; i <= k; i++) {
int curIndex = (index + i * direction) % length;
if (curIndex < 0)
curIndex += length;
sum += code[curIndex];
}
return sum;
}
}
```