How are people getting such high scores as 9x10^18 in Temple Run?

Solution 1:

What is more than likely happening is that these users are hacking these scores. A quick Google search will reveal software that you can obtain by jailbreaking your iOS device, allowing you to hack whatever score you wish to send to the Game Center leaderboards.

If you look at the All-Time High Scores for Temple Run, the highest score you will see is 9,223,372,036,854,775,807 or 2^63 - 1, which just so happens to be the largest signed integer that can be stored within 64 bits of data (see this Wikipedia article). These users likely tried to fake the highest score they could, but the leaderboard cannot store any value higher than the one shown above.

(Another common number seen faked in leaderboards is 2,147,483,647 (2^31 - 1), the largest signed integer that can be stored in 32 bits of data.)

Solution 2:

As fireDude67 points out, there is a glitch in the game that causes the path to be continuously straight and free of obstacles.

To perform the cheat:

1. Enable the Tutorial mode and start a game
2. On the first turn, swiftly perform the gesture to turn, twice; practically simultaneously (see demonstration).
3. The character will now run forever, until you trip twice and cause the apes to eat you.

There don't appear to be any coins or bonuses after glitching, so by my rough calculations I estimate that you'll earn about 500 points per second.

So to get a billion points, it would take about 23 days. The all-time high score (and possibly maximum score as it is tied five ways) of 9,223,372,036,854,775,807 would take nearly 600 million years. So maybe there's a way to glitch a coined path, or maybe that number is somehow significant in computing. The mystery remains.