0977.cpp

// Intuitive solution
class Solution {
  public:
    vector<int> sortedSquares(vector<int> &nums) {
        vector<int> res;
        int i = 0, j = nums.size() - 1;
        while (i <= j) {
            int n1 = nums[i] * nums[i];
            int n2 = nums[j] * nums[j];
            if (n1 > n2) {
                res.push_back(n1);
                i++;
            } else {
                res.push_back(n2);
                j--;
            }
        }
        reverse(res.begin(), res.end());
        return res;
    }
};

// Intuitive solution, better execution
// avoids recomputation of squares
// avoids reversal of the array
class Solution {
  public:
    vector<int> sortedSquares(vector<int> &nums) {
        int n = nums.size(), i = 0, j = nums.size() - 1;
        vector<int> res(n);
        for_each(nums.begin(), nums.end(), [](int &a) { a *= a; });
        while (i <= j)
            res[--n] = nums[i] > nums[j] ? nums[i++] : nums[j--];
        return res;
    }
};