Rename shared packages by day instead of vaguely by purpose.

2018/day07-1.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"strings"
 
-	"internal/tree"
+	"internal/day07"
 	"internal/util"
 )
 
@@ -12,10 +12,10 @@ func main() {
 	data := util.ReadInput()
 
 	// Build a tree of dependencies.
-	root := tree.BuildDependencyTree(data)
+	root := day07.BuildDependencyTree(data)
 
 	// Walk the tree and determine the correct ordering.
-	order := tree.FindOrder(root)
+	order := day07.FindOrder(root)
 
 	output := strings.Builder{}
 	for _, node := range order {