Hi Kamila,
In order to best guide you to this answer, it is important that you understand the differences between a fixed and growth mindset. Fixed mindsets believe that skills, intellect and situations are unchangeable. These people are afraid to fail, avoid challenges and desire to look smart. A person with a growth mindset knows that situations, intellect, and character can develop overtime with hard work. Their desire to learn and constantly challenge themselves allows them to grow. These people are not afraid to fail and they constantly put in effort to learn and change. Since I have not read 'The Stranger' I would recommend analyzing the qualities these characters have and see if they have either a growth or fixed mindset.