1652. Defuse the Bomb

Problem

Difficulty: Easy
Tags: Mid Level, Array, Sliding Window, Biweekly Contest 39

Intuition

This seemed pretty easy because I can just loop through array and find the new value for each.

Approach

since k is unchanged during the function call, I can just use if statement to determine which algorithm to use.

and it is really straight forward. i just used double for loop but I could do it in better complexity by removing code[i] from sum and adding code[i+k] to the sum for walking through code.

Solution

class Solution:
    def decrypt(self, code: List[int], k: int) -> List[int]:
        result = []
        n = len(code)
        for i in range(n):
            sum = 0
            if k == 0:
                result.append(0)
            elif k > 0:
                for j in range(k):
                    sum += code[(i+j+1+n)%n]
                result.append(sum)
            else:
                for j in range(-1*k):
                    sum += code[(i-j-1+n)%n]
                result.append(sum)
        return result

Complexity

Time: $O(n^2)$
Space: $O(n)$

Thoughts

This one was pretty easy. I didn’t actually used sliding window, but It worked.