Squares of a Sorted Array

/*
 * Problem : Sorted squares.
 * Input   : n, then n sorted integers.
 * Output  : n squares.
 * Approach: Two pointers.
 * Time    : O(n)
 * Space   : O(n)
 * Java    : 8 or newer.
 */
import java.util.Scanner;
import java.util.Arrays;
import java.util.stream.Collectors;

public class Main {
    // This method solves the task. It receives the input and returns the answer.
    static int[] solve(int[] a) {
        // Step 1: The biggest square is at one of the two ends, because negative numbers have big squares too.
        int[] result = new int[a.length];
        int left = 0;
        int right = a.length - 1;
        // Step 2: Fill the result from the back. Always take the end with the bigger absolute value.
        for (int position = a.length - 1; position >= 0; position--) {
            if (Math.abs(a[left]) > Math.abs(a[right])) {
                result[position] = a[left] * a[left];
                left++;
            } else {
                result[position] = a[right] * a[right];
                right--;
            }
        }
        return result;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int size = scanner.nextInt();
        int[] a = new int[size];
        for (int i = 0; i < size; i++) {
            a[i] = scanner.nextInt();
        }
        System.out.println(Arrays.stream(solve(a)).mapToObj(String::valueOf).collect(Collectors.joining(" ")));
    }
}