Brute force
Problems solved by brute force, including trying every number in a range, all permutations and subsets, digit puzzles and rebuses, small boards and combination locks, and checking every pair or triple when the input is small.
The backtracking and recursion articles in the Basics section explain how to enumerate options and cut branches early. Related problem sets are under Bitmasks and Meet-in-the-middle.
Problems
Three-digit numbers 2#9992
Very easy
Three-digit numbers 3#9993
Very easy
Three-digit numbers 4#9994
Very easy
Three-digit numbers 7#9997
Very easy
Three-digit numbers 8#9998
Very easy
Three-digit Armstrong numbers#9999
Very easy
Sticks#10001
Hard
Corona2020#10029
Very easy
Squares#10138
Easy
Increasing sines#10145
Very easy
iCow#10150
Easy
Bacteria#10216
Medium
The same number of divisors#10218
Very easy
Perfect Squares#10228
Very hard
N Queens - placement#10236
Very easy
Knight route#10242
Medium