/// <summary>
/// Solves the grid in-place.
/// </summary>
/// <param name="grid">
/// The grid to solve. This grid will be modified to contain the solution to
/// the sudoku puzzle, if it exists.
/// </param>
/// <returns>
/// If the puzzle can be unambiguously solved, Solve() will return true.
/// If the puzzle cannot be solved or has more than one solution,
/// this will return false.
/// </returns>
public bool Solve(Grid grid)
{
int numSolutions = 0;
Grid solutionGrid = grid.Copy();
if (FindErrors(grid).Count > 0)
{
// fail fast!
return(false);
}
// this bit here GREATLY simplifies DepthFirstSearch.
// Using exceptions and a lambda to terminate after two
// solutions frees DepthFirstSearch from worrying about
// all that logic at the cost of a closure and tricky
// exception handling.
// all of this is to avoid C#'s lack of generators, buh
try {
DepthFirstSearch(grid, () => {
// this lambda gets run on each solution
numSolutions++;
solutionGrid = grid.Copy();
if (numSolutions > 1)
{
throw new StopIterationException();
}
});
}
catch (StopIterationException e) { }
// (just pretend that empty catch block is a generator)
grid.CopyFrom(solutionGrid);
return(numSolutions == 1);
}
/// <summary>
/// Solves the grid in-place.
/// </summary>
/// <param name="grid">
/// The grid to solve. This grid will be modified to contain the solution to
/// the sudoku puzzle, if it exists.
/// </param>
/// <returns>
/// If the puzzle can be unambiguously solved, Solve() will return true.
/// If the puzzle cannot be solved or has more than one solution,
/// this will return false.
/// </returns>
public bool Solve(Grid grid)
{
int numSolutions = 0;
Grid solutionGrid = grid.Copy();
if (FindErrors(grid).Count > 0)
{
// fail fast!
return false;
}
// this bit here GREATLY simplifies DepthFirstSearch.
// Using exceptions and a lambda to terminate after two
// solutions frees DepthFirstSearch from worrying about
// all that logic at the cost of a closure and tricky
// exception handling.
// all of this is to avoid C#'s lack of generators, buh
try {
DepthFirstSearch(grid, () => {
// this lambda gets run on each solution
numSolutions++;
solutionGrid = grid.Copy();
if (numSolutions > 1) {
throw new StopIterationException();
}
});
}
catch (StopIterationException e) { }
// (just pretend that empty catch block is a generator)
grid.CopyFrom(solutionGrid);
return numSolutions == 1;
}
