Python ] leetCode 189 - Rotate Array

 

 

리트코드 189번 문제

 

Given an integer array nums, rotate the array to the right by k steps, where k is non-negative.

 

 

Example 1:

• Input: nums = [1,2,3,4,5,6,7], k = 3
• Output: [5,6,7,1,2,3,4]
• Explanation: rotate 1 steps to the right: [7,1,2,3,4,5,6] rotate 2 steps to the right: [6,7,1,2,3,4,5] rotate 3 steps to the right: [5,6,7,1,2,3,4]

 

 

Example 2:

• Input: nums = [-1,-100,3,99], k = 2
• Output: [3,99,-1,-100]
• Explanation: rotate 1 steps to the right: [99,-1,-100,3] rotate 2 steps to the right: [3,99,-1,-100]

 

 

Constraints:

• 1 <= nums.length <= 105
• -231 <= nums[i] <= 231 - 1
• 0 <= k <= 105

 

 

k의 범위가 0부터 10^5까지니까 0이 아닌 나머지값에 대해서만 이동하면 되고, 추가적으로 기존 리스트를 기억할 메모리를 확보해 O(n) 복잡도로 해결한다.

 

class Solution:
    def rotate(self, nums: List[int], k: int) -> None:
        """
        Do not return anything, modify nums in-place instead.
        """
        length = len(nums)
        remainder = k % length
        if remainder == 0:
            return
        temp = nums.copy()
        for i in range(remainder):
            nums[i] = temp[length - remainder + i]
        for i in range(length - remainder):
            nums[remainder + i] = temp[i]