Sudoku solving algorithm C++

Question

I\'m trying to make a Sudoku Solving program for a couple of days but I\'m stuck with the methods. I found this algorithm here but I don\'t really understand it:

Answer 1

This is a classic Constraint Satisfaction Problem. I recommend doing some research on the topic to figure out the successful strategy. You will need to use AC-3 ( Arc Consistency 3) algorithm along with the backtracking techniques to solve the problem.