The request is to rotate a list. When K=3, you turn [1,2,3,4,5,6,7] into [5,6,7,1,2,3,4]; when K=1, you turn [1,2,3,4,5,6,7] into [7,1,2,3,4,5,6]
Why am I out of range?
PyCharm informed me like this: IndexError: list index out of range
class Solution:
def rotate(self, nums, k) -> None:
k = k%len(nums)
def rev(x, y, num):
while y > x:
num[x], num[y] = num[y], num[x]
x += 1
y -= 1
rev(0, len(nums), nums)
rev(0, k-1,nums)
rev(k, len(nums), nums)
nums = [1,2,3,4,5,6,7]
s = Solution()
s.rotate(nums,3)
you're getting an index out of range error because you're trying to access an index in the list that doesn't exist.
Typically, your list nums has 7 elements which means you can do nums[i] if 0<=i<=6.
To fix your code you just need to replace rev(0, len(nums), nums) by rev(0, len(nums)-1, nums)
class Solution:
def rotate(self, nums, k) -> None:
k = k % len(nums)
def rev(x, y, num):
while y > x:
num[x], num[y] = num[y], num[x]
x += 1
y -= 1
rev(0, len(nums)-1, nums)
rev(0, k - 1, nums)
rev(k, len(nums)-1, nums)
nums = [1, 2, 3, 4, 5, 6, 7]
s = Solution()
s.rotate(nums, 3)
Alternatively, you can use this simpler implementation which returns another list:
class Solution:
def rotate(self, nums, k) -> list:
k = k % len(nums)
return nums[-k:] + nums[:-k]
nums = [1, 2, 3, 4, 5, 6, 7]
s = Solution()
nums = s.rotate(nums, 3)