add filter function to filter zwires from wires

day-24/internal/one/util.go

@@ -13,7 +13,7 @@ const (
 	target
 )
 
-func parseLines(r io.Reader) (map[string]int, map[string]int, []expression, error) {
+func parseLines(r io.Reader) (map[string]int, []expression, error) {
 	initial := make(map[string]int)
 	wires := make(map[string]int)
 	expressions := []expression{}
@@ -52,10 +52,14 @@ func parseLines(r io.Reader) (map[string]int, map[string]int, []expression, erro
 	}
 
 	if err := scanner.Err(); err != nil {
-		return nil, nil, nil, err
+		return nil, nil, err
 	}
 
-	return initial, wires, expressions, nil
+	for k, v := range initial {
+		wires[k] = v
+	}
+
+	return wires, expressions, nil
 }
 
 func mustConv(s string) int {
@@ -82,3 +86,13 @@ func mustConvBinToDec(s string) int {
 	}
 	return int(n)
 }
+
+func filter(wires map[string]int, fn func(string) bool) []zWire {
+	var filtered []zWire
+	for name, value := range wires {
+		if fn(name) {
+			filtered = append(filtered, zWire{name, value})
+		}
+	}
+	return filtered
+}