15. Squares of a Sorted Array.cpp

/*
Squares of a Sorted Array
=========================

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.
*/

class Solution
{
public:
  vector<int> sortedSquares(vector<int> &nums)
  {
    vector<int> ans;
    int i = 0, j = nums.size() - 1;
    while (i <= j)
    {
      if (nums[i] * nums[i] > nums[j] * nums[j])
      {
        ans.insert(ans.begin(), nums[i] * nums[i]);
        i++;
      }
      else
      {
        ans.insert(ans.begin(), nums[j] * nums[j]);
        j--;
      }
    }
    return ans;
  }
};