leetcode-189-旋转数组

小灰灰 2021-11-29 23:48 312阅读 0赞

题目描述：

![1509441-20190720135353349-1407527242.png][]

方法一：

class Solution:
        def rotate(self, nums: List[int], k: int) -> None:
            """
            Do not return anything, modify nums in-place instead.
            """
            for i in range(k):
                temp = nums[-1]
                del nums[-1]
                nums.insert(0,temp)

另：

k=k%len(nums)
            for i in range(k):
                nums.insert(0,nums.pop())

方法二;

class Solution:
        def rotate(self, nums: List[int], k: int) -> None:
            """
            Do not return anything, modify nums in-place instead.
            """
            k=k%len(nums)
            t=nums[-k:]
            nums[k:]=nums[:-k]
            nums[:k]=t

方法三：

class Solution:
        def rotate(self, nums: List[int], k: int) -> None:
            """
            Do not return anything, modify nums in-place instead.
            """
            n=len(nums) 
            k=k%n 
            self.reverse(nums,0,n-1) 
            self.reverse(nums,0,k-1) 
            self.reverse(nums,k,n-1) 
    
        def reverse(self,nums,start,end): 
            while start<end: 
                nums[start],nums[end]=nums[end],nums[start] 
                start+=1 
                end-=1

方法四：环状替代

class Solution:
        def rotate(self, nums: List[int], k: int) -> None:
            """
            Do not return anything, modify nums in-place instead.
            """
            k=k%len(nums)
            count = 0
            for start in range(len(nums)):
                if count<len(nums):
                    current=start
                    prev = nums[start]
                    while True:
                        next = (current+k)%len(nums)
                        temp = nums[next]
                        nums[next] = prev
                        prev=temp
                        current = next
                        count+=1
                        if start==current:
                            break

转载于:https://www.cnblogs.com/oldby/p/11217637.html

[1509441-20190720135353349-1407527242.png]: /images/20211129/dbb2564341064ead85a2c7e67534ca49.png