Our combination lock picker works by using an improved brute force algorithm to test every possible combination of a lock. The first trick is to realize cheap combination locks have a tolerance of +/- 1 on each of the numbers. This means that even if you are off in either direction by 1, the lock will still open. This cuts the number of combinations we must test from 64000 to 2197. Next, we realized we could avoid re-inputting the first number every time we test a new second number. For instance, we could test 12-10-8 and 12-7-8 without having to re-input 12. This is because the first plate of the lock is not disturbed when you turn the dial back to test the third number if you do not turn the dial past the second number. Finally, you can test every possible third number without re-inputting the first two. You simply try every third number, and if the combination is right, the lock will open. For example, we can try every combination from 12-10-7, 12-10-6, 12-10-5... all the! way back to 12-10-8 without re-inputting the first two numbers. All of these tricks combined give us a worst-case scenario of any combination lock that fits into the machine of roughly 20 minutes.
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