**Frequency: 2/10**
Digit DP problems usually ask you to count the number of numbers in a range satisfying some certain conditions.
The problem statements for Digit DP typically have clear indications that the technique should be used. Hence, in a contest, it is essential to manage your time wisely when attempting Digit DP problems, as problem setters intentionally make them challenging to code.
Tip: When solving problems, consider using a different number base if necessary, such as base-2, to optimize time complexity.