/
multi_backtracking.go
63 lines (56 loc) · 1.18 KB
/
multi_backtracking.go
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package solver
import "github.com/chrismar035/sudoku-solver/grid"
type multiBacktrackingSolver struct{}
func (b multiBacktrackingSolver) Solve(given Grid) ([]Grid, error) {
var puzzle [81]backtrackSquare
for i, value := range given {
puzzle[i] = backtrackSquare{value: value, initial: value != 0}
}
var solutions []Grid
forward := true
i := 0
for {
if puzzle[i].initial {
if forward {
i++
} else {
i--
}
} else {
forward = true
puzzle[i].value++
ok := false
if puzzle[i].value > 9 {
puzzle[i].value = 0
forward = false
i--
} else {
ok = checkValues(grid.IndicesForColumn(i), puzzle[i].value, puzzle)
if ok {
ok = checkValues(grid.IndicesForRow(i), puzzle[i].value, puzzle)
}
if ok {
ok = checkValues(grid.IndicesForSub(i), puzzle[i].value, puzzle)
}
}
if ok {
i++
}
}
if i >= 81 {
// Puzzle is done record this solution and go back and find more
var ended [81]int
for i, square := range puzzle {
ended[i] = square.value
}
solutions = append(solutions, ended)
forward = false
i--
}
if i <= 0 {
// Found all the solutions
break
}
}
return solutions, nil
}