import java.util.Arrays;

public class BallSorter {
    public static void main(String[] args) {
        char[] balls = {'r', 'g', 'r', 'g', 'g', 'r'};

        int left = 0;
        int right = balls.length - 1;

        while (left < right) {
            // Move left pointer if it's already green
            while (left < right && balls[left] == 'g') {
                left++;
            }

            // Move right pointer if it's already red
            while (left < right && balls[right] == 'r') {
                right--;
            }

            // Swap if out of place
            if (left < right) {
                char temp = balls[left];
                balls[left] = balls[right];
                balls[right] = temp;
                left++;
                right--;
            }
        }

        System.out.println("Sorted balls: " + Arrays.toString(balls));
    }
}