first successful run to solve a simple puzzle

logic/strategies/notes.go

@@ -0,0 +1,81 @@
+package strategies
+
+import (
+	"git.kleiax.de/homepage/board"
+)
+
+// ────────────────────────────────────────────────────────────────────────────── //
+// NOTES STRUCTURE                                                                //
+// ────────────────────────────────────────────────────────────────────────────── //
+
+type Notes struct {
+	Base
+}
+
+func (n *Notes) SearchProgressableCells() int {
+	n.field.ForEachRow(func(row *board.Row) {
+		row.ForEachCell(func(cell *board.Cell) {
+			column, _ := n.field.GetColumn(cell.Pos.GetColumn())
+			block, _ := n.field.GetBlock(cell.Pos.GetBlockRow(), cell.Pos.GetBlockColumn())
+			candidates := intersection3(row.GetMissingNumbers(), column.GetMissingNumbers(), block.GetMissingNumbers())
+			for _, note := range candidates {
+				if cell.Notes.Has(note) || cell.GetNumber() != 0 {
+					continue
+				}
+				ch := board.ExternalChange{
+					Cell:       cell,
+					Action:     board.ActionSetNote,
+					Value:      note,
+					TriggerdBy: n.getName(),
+					Marks:      nil,
+					From:       0,
+				}
+				n.changes = append(n.changes, ch)
+			}
+		})
+	})
+	return len(n.changes)
+}
+
+func (n *Notes) getName() string {
+	return "Make Notes"
+}
+
+func intersection3(a, b, c []int) []int {
+	set := make(map[int]bool)
+
+	for _, v := range a {
+		set[v] = true
+	}
+
+	// Nur Werte behalten, die auch in b vorkommen
+	inB := make(map[int]bool)
+	for _, v := range b {
+		inB[v] = true
+	}
+
+	for v := range set {
+		if !inB[v] {
+			delete(set, v)
+		}
+	}
+
+	// Nur Werte behalten, die auch in c vorkommen
+	inC := make(map[int]bool)
+	for _, v := range c {
+		inC[v] = true
+	}
+
+	for v := range set {
+		if !inC[v] {
+			delete(set, v)
+		}
+	}
+
+	result := make([]int, 0, len(set))
+	for v := range set {
+		result = append(result, v)
+	}
+
+	return result
+}