146 lines
2.5 KiB
V
146 lines
2.5 KiB
V
struct Empty {}
|
|
|
|
struct Node<T> {
|
|
value T
|
|
left Tree<T>
|
|
right Tree<T>
|
|
}
|
|
|
|
type Tree<T> = Empty | Node<T>
|
|
|
|
// return size(number of nodes) of BST
|
|
fn size<T>(tree Tree<T>) int {
|
|
return match tree {
|
|
Empty { 0 }
|
|
Node<T> { 1 + size<T>(tree.left) + size<T>(tree.right) }
|
|
}
|
|
}
|
|
|
|
// insert a value to BST
|
|
fn insert<T>(tree Tree<T>, x T) Tree<T> {
|
|
return match tree {
|
|
Empty {
|
|
Node<T>{x, tree, tree}
|
|
}
|
|
Node<T> {
|
|
if x == tree.value {
|
|
tree
|
|
} else if x < tree.value {
|
|
Node<T>{
|
|
...tree
|
|
left: insert<T>(tree.left, x)
|
|
}
|
|
} else {
|
|
Node<T>{
|
|
...tree
|
|
right: insert<T>(tree.right, x)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// whether able to find a value in BST
|
|
fn search<T>(tree Tree<T>, x T) bool {
|
|
return match tree {
|
|
Empty {
|
|
false
|
|
}
|
|
Node<T> {
|
|
if x == tree.value {
|
|
true
|
|
} else if x < tree.value {
|
|
search<T>(tree.left, x)
|
|
} else {
|
|
search<T>(tree.right, x)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// find the minimal value of a BST
|
|
fn min<T>(tree Tree<T>) T {
|
|
return match tree {
|
|
Empty {
|
|
1e100
|
|
}
|
|
Node<T> {
|
|
if tree.value < min<T>(tree.left) {
|
|
tree.value
|
|
} else {
|
|
min<T>(tree.left)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// delete a value in BST (if nonexistant do nothing)
|
|
fn delete<T>(tree Tree<T>, x T) Tree<T> {
|
|
return match tree {
|
|
Empty {
|
|
tree
|
|
}
|
|
Node<T> {
|
|
if tree.left is Node<T> && tree.right is Node<T> {
|
|
if x < tree.value {
|
|
Node<T>{
|
|
...tree
|
|
left: delete<T>(tree.left, x)
|
|
}
|
|
} else if x > tree.value {
|
|
Node<T>{
|
|
...tree
|
|
right: delete<T>(tree.right, x)
|
|
}
|
|
} else {
|
|
Node<T>{
|
|
...tree
|
|
value: min<T>(tree.right)
|
|
right: delete<T>(tree.right, min<T>(tree.right))
|
|
}
|
|
}
|
|
} else if tree.left is Node<T> {
|
|
if x == tree.value {
|
|
tree.left
|
|
} else {
|
|
Node<T>{
|
|
...tree
|
|
left: delete<T>(tree.left, x)
|
|
}
|
|
}
|
|
} else {
|
|
if x == tree.value {
|
|
tree.right
|
|
} else {
|
|
Node<T>{
|
|
...tree
|
|
right: delete<T>(tree.right, x)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn test_generics_complex_sumtype() {
|
|
mut tree := Tree<f64>(Empty{})
|
|
input := [0.3, 0.2, 0.5, 0.0, 0.6, 0.8, 0.9, 1.0, 0.1, 0.4, 0.7]
|
|
for i in input {
|
|
tree = insert(tree, i)
|
|
}
|
|
println('[1] after insertion tree size is ${size(tree)}') // 11
|
|
del := [-0.3, 0.0, 0.3, 0.6, 1.0, 1.5]
|
|
for i in del {
|
|
tree = delete(tree, i)
|
|
}
|
|
print('[2] after deletion tree size is ${size(tree)}, ') // 7
|
|
print('and these elements were deleted: ') // 0.0 0.3 0.6 1.0
|
|
for i in input {
|
|
if !search(tree, i) {
|
|
print('$i ')
|
|
}
|
|
}
|
|
println('')
|
|
assert size(tree) == 7
|
|
}
|