// Solve solves the given sudoku puzzle and returns whether it was successful
func (b *Board) Solve() bool {
root := dlx.NewRoot()
sideLen := b.sideLen()
solution := make(chan int, sideLen*sideLen)
solved := false
b.genSparseMatrix(root)
for r, row := range b.grid {
for c, v := range row {
if v != 0 {
n := dlx.Find(b.possibility(r, c, v-1), root)
if n == nil {
return false
}
dlx.Cover(n)
}
}
}
func() {
defer close(solution)
solved = dlx.Solve(root, solution)
}()
for poss := range solution {
b.togglePossibility(poss)
}
return solved
}
// Solve solves the given sudoku puzzle and returns whether it was successful
func (g *Grid) Solve() bool {
root := dlx.NewRoot()
solution := make(chan int, numCells)
solved := false
genSparseMatrix(root)
for r, row := range g {
for c, v := range row {
if v != 0 {
n := dlx.Find(possibility(r, c, v-1), root)
if n == nil {
return false
}
dlx.Cover(n)
}
}
}
func() {
defer close(solution)
solved = dlx.Solve(root, solution)
}()
for poss := range solution {
g.togglePossibility(poss)
}
return solved
}
// SolveAndRank solves the given sudoku puzzle and returns whether it is
// successful and its rank.
func (g *Grid) SolveAndRank() (bool, string) {
root := dlx.NewRoot()
solution := make(chan int, numCells)
solutions, givens := 0, 0
genSparseMatrix(root)
for r, row := range g {
for c, v := range row {
if v != 0 {
n := dlx.Find(possibility(r, c, v-1), root)
if n == nil {
return false, ""
}
dlx.Cover(n)
givens++
}
}
}
go func() {
defer close(solution)
solutions = dlx.SolveAll(root, solution)
}()
for poss := range solution {
if givens != numCells {
filled := g.togglePossibility(poss)
if !filled {
givens--
} else {
givens++
}
}
}
message := rankMessage(rankGivens(givens, solutions))
return solutions > 0, message
}
