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 thei-th
number with the sum of the nextk
numbers. - If
k < 0
, replace thei-th
number with the sum of the previousk
numbers. - If
k == 0
, replace thei-th
number with0
.
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;
}
}