# 2022-05-16

Given an integer array

`nums`

sorted in **non-decreasing**order, return*an array of**the squares of each number**sorted in non-decreasing order*.**Example 1:**

Input: nums = [-4,-1,0,3,10]

Output: [0,1,9,16,100]

Explanation: After squaring, the array becomes [16,1,0,9,100].

After sorting, it becomes [0,1,9,16,100].

**Example 2:**

Input: nums = [-7,-3,2,3,11]

Output: [4,9,9,49,121]

**Constraints:**

`1 <= nums.length <= 10^4`

`-10^4 <= nums[i] <= 10^4`

`nums`

is sorted in**non-decreasing**order.

**Follow up:**Squaring each element and sorting the new array is very trivial, could you find an

`O(n)`

solution using a different approach?func sortedSquares(nums []int) []int {

length := len(nums)

left, right := 0, length-1

res := make([]int, length)

for pos := length - 1; pos >= 0; pos-- {

if l, r := nums[left]*nums[left], nums[right]*nums[right]; l > r {

res[pos] = l

left++

} else {

res[pos] = r

right--

}

}

return res

}

Given an array, 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`

**Follow up:**

- Try to come up with as many solutions as you can. There are at least
**three**different ways to solve this problem. - Could you do it in-place with
`O(1)`

extra space?

func rev(nums []int) {

length := len(nums)

for i, j := 0, length-1; i < length/2; i++ {

nums[i], nums[j-i] = nums[j-i], nums[i]

}

}

func rotate(nums []int, k int) {

k %= len(nums)

rev(nums)

rev(nums[k:])

rev(nums[:k])

}

Last modified 10mo ago