0
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package takuzu |
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import ( |
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"fmt" |
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"log" |
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"math/rand" |
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"time" |
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"github.com/pkg/errors" |
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) |
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func init() { |
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rand.Seed(time.Now().UTC().UnixNano()) |
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} |
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type buildTakuzuOptions struct { |
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size int |
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minRatio, maxRatio int |
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simple bool |
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buildBoardTimeout, reduceBoardTimeout time.Duration |
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} |
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// ReduceBoard randomly removes as many numbers as possible from the |
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// takuzu board and returns a pointer to the new board. |
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// The initial takuzu might be modified. |
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func (tak Takuzu) ReduceBoard(trivial bool, wid string, buildBoardTimeout, reduceBoardTimeout time.Duration) (*Takuzu, error) { |
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size := tak.Size |
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// First check if the board is correct |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: Checking for all grid solutions...", wid) |
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} |
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allSol := &[]Takuzu{} |
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_, err := tak.Clone().TrySolveRecurse(allSol, buildBoardTimeout) |
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ns := len(*allSol) |
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if err != nil && errors.Cause(err).Error() == "timeout" { |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: There was a timeout (%d resolution(s) found).", wid, ns) |
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} |
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if ns == 0 { |
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return nil, err |
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} |
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//if ns < 10 { return nil, err } |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: Going on anyway...", wid) |
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} |
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} |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: %d solution(s) found.", wid, ns) |
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} |
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if ns == 0 { |
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return nil, err |
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} else if ns > 1 { |
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tak = (*allSol)[rand.Intn(ns)] |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: Warning: there are %d solutions.", wid, ns) |
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log.Printf("[%v]ReduceBoard: Picking one randomly.", wid) |
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if verbosity > 1 { |
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tak.DumpBoard() |
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fmt.Println() |
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} |
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} |
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allSol = nil |
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} else { |
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// 1 and only 1 solution |
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if verbosity > 1 { |
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tak.DumpBoard() |
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fmt.Println() |
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} |
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} |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: Grid reduction...", wid) |
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} |
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fields := make([]*Cell, size*size) |
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n := 0 |
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for l := range tak.Board { |
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for c := range tak.Board[l] { |
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if tak.Board[l][c].Defined { |
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fields[n] = &tak.Board[l][c] |
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n++ |
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} |
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} |
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} |
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nDigits := 0 |
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initialDigits := n |
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ratio := 0 |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: %d%%", wid, ratio) |
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} |
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for ; n > 0; n-- { |
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var rollback bool |
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i := rand.Intn(n) |
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fields[i].Defined = false |
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if trivial { |
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full, err := tak.Clone().TrySolveTrivial() |
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if err != nil || !full { |
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rollback = true |
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} |
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} else { |
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allSol = &[]Takuzu{} |
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_, err := tak.Clone().TrySolveRecurse(allSol, reduceBoardTimeout) |
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if err != nil || len(*allSol) != 1 { |
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rollback = true |
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} |
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} |
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if rollback { |
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if verbosity > 1 { |
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log.Printf("[%v]ReduceBoard: Backing out", wid) |
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} |
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fields[i].Defined = true // Back out! |
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nDigits++ |
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} |
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fields = append(fields[:i], fields[i+1:]...) |
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if verbosity > 0 { |
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nr := (initialDigits - n) * 100 / initialDigits |
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if nr > ratio { |
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ratio = nr |
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log.Printf("[%v]ReduceBoard: %d%%", wid, ratio) |
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} |
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} |
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} |
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if verbosity > 0 { |
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log.Printf("[%v]ReduceBoard: I have left %d digits.", wid, nDigits) |
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} |
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return &tak, nil |
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} |
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// newRandomTakuzu creates a new Takuzu board with a given size |
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// It is intended to be called by NewRandomTakuzu only. |
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func newRandomTakuzu(wid string, buildOpts buildTakuzuOptions) (*Takuzu, error) { |
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size := buildOpts.size |
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easy := buildOpts.simple |
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buildBoardTimeout := buildOpts.buildBoardTimeout |
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reduceBoardTimeout := buildOpts.reduceBoardTimeout |
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minRatio := buildOpts.minRatio |
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maxRatio := buildOpts.maxRatio |
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tak := New(size) |
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n := size * size |
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fields := make([]*Cell, n) |
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i := 0 |
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for l := range tak.Board { |
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for c := range tak.Board[l] { |
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fields[i] = &tak.Board[l][c] |
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i++ |
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} |
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} |
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if verbosity > 0 { |
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log.Printf("[%v]NewRandomTakuzu: Filling new board (%dx%[2]d)...", wid, size) |
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} |
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nop := 0 |
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// #1. Loop until the ratio of empty cells is less than minRatio% (e.g. 55%) |
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for n > size*size*minRatio/100 { |
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i := rand.Intn(n) |
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fields[i].Defined = true |
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fields[i].Value = rand.Intn(2) |
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var err error |
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if _, err = tak.Validate(); err != nil { |
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if verbosity > 1 { |
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log.Printf("[%v]NewRandomTakuzu: Could not set cell value to %v", wid, fields[i].Value) |
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} |
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} else if _, err = tak.Clone().TrySolveTrivial(); err != nil { |
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if verbosity > 1 { |
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log.Printf("[%v]NewRandomTakuzu: Trivial checks: Could not set cell value to %v", wid, fields[i].Value) |
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} |
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} |
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if err == nil { |
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fields = append(fields[:i], fields[i+1:]...) |
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n-- |
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continue |
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} |
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// If any of the above checks fails, we roll back |
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fields[i].Defined = false |
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fields[i].Value = 0 // Let's reset but it is useless |
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// Safety check to avoid deadlock on bad boards |
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nop++ |
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if nop > 2*size*size { |
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log.Printf("[%v]NewRandomTakuzu: Could not fill up board!", wid) |
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// Givin up on this board |
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return nil, errors.New("could not fill up board") // Try again |
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} |
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} |
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var ptak *Takuzu |
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var removed int |
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// #2. Try to solve the current board; try to remove some cells if it fails |
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// Initial empty cells count |
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iecc := n |
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for { |
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// Current count of empty (i.e. undefined) cells |
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ec := iecc + removed |
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ecpc := ec * 100 / (size * size) |
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if verbosity > 0 { |
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log.Printf("[%v]NewRandomTakuzu: Empty cells: %d (%d%%)", wid, ec, ecpc) |
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} |
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if ecpc > maxRatio { |
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if verbosity > 0 { |
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log.Printf("[%v]NewRandomTakuzu: Too many empty cells (%d); giving up on this board", wid, ec) |
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} |
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break |
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} |
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var err error |
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ptak, err = tak.ReduceBoard(easy, wid, buildBoardTimeout, reduceBoardTimeout) |
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if err != nil && errors.Cause(err).Error() == "timeout" { |
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break |
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} |
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if err == nil && ptak != nil { |
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break |
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} |
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if verbosity > 0 { |
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log.Printf("[%v]NewRandomTakuzu: Could not use this grid", wid) |
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} |
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inc := size * size / 150 |
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if inc == 0 { |
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inc = 1 |
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} |
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tak.removeRandomCell(inc) |
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removed += inc |
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if verbosity > 1 { |
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log.Printf("[%v]NewRandomTakuzu: Removed %d numbers", wid, removed) |
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if verbosity > 1 { |
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tak.DumpBoard() |
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} |
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} |
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} |
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if ptak == nil { |
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if verbosity > 0 { |
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log.Printf("[%v]NewRandomTakuzu: Couldn't use this board, restarting from scratch...", wid) |
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} |
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return nil, errors.New("could not use current board") // Try again |
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} |
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return ptak, nil |
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} |
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// NewRandomTakuzu creates a new Takuzu board with a given size |
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func NewRandomTakuzu(size int, simple bool, wid string, buildBoardTimeout, reduceBoardTimeout time.Duration, minRatio, maxRatio int) (*Takuzu, error) { |
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if size%2 != 0 { |
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return nil, errors.New("board size should be an even value") |
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} |
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if size < 4 { |
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return nil, errors.New("board size is too small") |
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} |
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// minRatio : percentage (1-100) of empty cells when creating a new board |
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// If the board is wrong the cells will be removed until we reach maxRatio |
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if minRatio < 40 { |
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minRatio = 40 |
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} |
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if minRatio > maxRatio { |
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return nil, errors.New("minRatio/maxRatio incorrect") |
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} |
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if maxRatio > 99 { |
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maxRatio = 99 |
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} |
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buildOptions := buildTakuzuOptions{ |
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size: size, |
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minRatio: minRatio, |
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maxRatio: maxRatio, |
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simple: simple, |
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buildBoardTimeout: buildBoardTimeout, |
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reduceBoardTimeout: reduceBoardTimeout, |
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} |
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var takP *Takuzu |
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for { |
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var err error |
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takP, err = newRandomTakuzu(wid, buildOptions) |
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if err == nil { |
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break |
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} |
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} |
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return takP, nil |
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} |
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func (tak Takuzu) removeRandomCell(number int) { |
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size := tak.Size |
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fields := make([]*Cell, size*size) |
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n := 0 |
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for l := range tak.Board { |
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for c := range tak.Board[l] { |
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if tak.Board[l][c].Defined { |
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fields[n] = &tak.Board[l][c] |
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n++ |
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} |
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} |
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} |
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for i := 0; i < number; i++ { |
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if n == 0 { |
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return |
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} |
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fields[rand.Intn(n)].Defined = false |
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fields = append(fields[:i], fields[i+1:]...) |
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n-- |
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} |
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} |