52 lines
1.2 KiB
Go
52 lines
1.2 KiB
Go
|
package tree
|
||
|
|
|
||
|
|
import "fmt" // debug
|
||
|
|
|
||
|
|
// FindOrder determines the correct order according to these rules:
|
||
|
|
// 1. A node cannot come before all of its parents have been included.
|
||
|
|
// 2. At any given time, the lowest-lettered step must be executed.
|
||
|
|
func FindOrder(root *Node) []*Node {
|
||
|
|
seen := make(map[rune]bool)
|
||
|
|
return findOrderR(root, seen)
|
||
|
|
}
|
||
|
|
|
||
|
|
func findOrderR(node *Node, seen map[rune]bool) []*Node {
|
||
|
|
order := []*Node{}
|
||
|
|
|
||
|
|
// debug
|
||
|
|
fmt.Printf("In node: %c | Children: ", node.Name)
|
||
|
|
for _, child := range node.Children {
|
||
|
|
fmt.Printf("%c ", child.Name)
|
||
|
|
}
|
||
|
|
fmt.Printf("| Parents: ")
|
||
|
|
for _, parent := range node.Parents {
|
||
|
|
fmt.Printf("%c ", parent.Name)
|
||
|
|
}
|
||
|
|
fmt.Println()
|
||
|
|
// end debug
|
||
|
|
|
||
|
|
// add the node, but only if all its parents have been seen
|
||
|
|
if len(node.Parents) == 0 {
|
||
|
|
seen[node.Name] = true
|
||
|
|
} else {
|
||
|
|
for _, parent := range node.Parents {
|
||
|
|
if _, ok := seen[parent.Name]; !ok {
|
||
|
|
return order
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if _, ok := seen[node.Name]; !ok {
|
||
|
|
order = append(order, node)
|
||
|
|
fmt.Printf("Added node: %c\n", node.Name)
|
||
|
|
seen[node.Name] = true
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// recurse
|
||
|
|
for _, child := range node.Children {
|
||
|
|
order = append(order, findOrderR(child, seen)...)
|
||
|
|
}
|
||
|
|
|
||
|
|
return order
|
||
|
|
}
|