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HardGraphsLC 753

Cracking the Safe

There is a safe protected by a password. The password is a sequence of n digits where each digit can be in the range [0, k - 1]. The safe has a peculiar way of checking the password. When you enter in a sequence, it checks the most recent n digits that were entered each time you type a digit. For example, the correct password is "345 " and you enter in "012345 ": After typing 0, the most recent 3 digits is "0 ", which is incorrect. After typing 1, the most recent 3 digits is "01 ", which is incorrect. After typing 2, the most recent 3 digits is "012 ", which is incorrect. After typing 3, the most recent 3 digits is "123 ", which is incorrect. After typing 4, the most recent 3 digits is "234 ", which is incorrect.

Asked at 1 company
Google
Hints
  • 1.Think about which data structure fits best
  • 2.Consider the time complexity of your approach
  • 3.Look for patterns in the constraints
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