Tell me the book:
The world of the future. Graduates of schools (or some particular school) are conducted a survival exam: students are thrown alone through a teleport to an uninhabited planet with the earth's climate, allowing to take only the most necessary, of choice.
The planet is the same for everyone, but they are sent with a spread of several kilometers: if you want - turn yourself, if you want - look for others. It takes about a week, then it is taken back.
Everything changes when, due to some galactic cataclysm, the teleport work is blocked for several years, and a group of graduates rely on a foreign planet.