One example is Sudoku. It's NP-hard, but in practice, it takes no time at all to solve your newspaper puzzle.
NP-hard just speaks about the algorithm complexity. The input size of a typical sudoku puzzles so small that even the most naive algorithm can do it quickly.
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NP-hard just speaks about the algorithm complexity. The input size of a typical sudoku puzzles so small that even the most naive algorithm can do it quickly.