leetcode-day3:Squares of a Sorted Array(有序数组的平方)

977. Squares of a Sorted Array
数组：有序数组的平方，还有序么？

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 <= 104
-104 <= nums[i] <= 104
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?

JAVA实现代码：

class Solution {
    public int[] sortedSquares(int[] nums) {
       int startIndex=0;
       int endIndex=nums.length-1;
       int k=nums.length-1;
       int[] result = new int[nums.length];
       for(;startIndex<=endIndex;){
           if(nums[startIndex]*nums[startIndex]