mirror of
https://github.com/appgurueu/modlib.git
synced 2024-08-19 04:44:11 +02:00
Add ranked set
This commit is contained in:
parent
6691a64484
commit
454ffb1a46
3
init.lua
3
init.lua
@ -74,7 +74,8 @@ for _, component in ipairs{
|
||||
"vector",
|
||||
"minetest",
|
||||
"trie",
|
||||
"heap"
|
||||
"heap",
|
||||
"ranked_set"
|
||||
} do
|
||||
modlib[component] = loadfile_exports(get_resource(component .. ".lua"))
|
||||
end
|
||||
|
312
ranked_set.lua
Normal file
312
ranked_set.lua
Normal file
@ -0,0 +1,312 @@
|
||||
local class = getfenv(1)
|
||||
local metatable = {__index = class}
|
||||
|
||||
comparator = modlib.table.default_comparator
|
||||
|
||||
--+ Uses a weight-balanced binary tree
|
||||
function new(comparator)
|
||||
return setmetatable({comparator = comparator, root = {total = 0}}, metatable)
|
||||
end
|
||||
|
||||
function len(self)
|
||||
return self.root.total
|
||||
end
|
||||
metatable.__len = len
|
||||
|
||||
function is_empty(self)
|
||||
return len(self) == 0
|
||||
end
|
||||
|
||||
local function insert_all(tree, _table)
|
||||
if tree.left then
|
||||
insert_all(tree.left, _table)
|
||||
end
|
||||
table.insert(_table, tree.key)
|
||||
if tree.right then
|
||||
insert_all(tree.right, _table)
|
||||
end
|
||||
end
|
||||
|
||||
function to_table(self)
|
||||
local table = {}
|
||||
if not is_empty(self) then
|
||||
insert_all(self.root, table)
|
||||
end
|
||||
return table
|
||||
end
|
||||
|
||||
--> iterator: function() -> `rank, key` with ascending rank
|
||||
function ipairs(self, min, max)
|
||||
if is_empty(self) then
|
||||
return function() end
|
||||
end
|
||||
min = min or 1
|
||||
local tree = self.root
|
||||
local current_rank = (tree.left and tree.left.total or 0) + 1
|
||||
repeat
|
||||
if min == current_rank then
|
||||
break
|
||||
end
|
||||
local left, right = tree.left, tree.right
|
||||
if min < current_rank then
|
||||
current_rank = current_rank - (left and left.right and left.right.total or 0) - 1
|
||||
tree = left
|
||||
else
|
||||
current_rank = current_rank + (right and right.left and right.left.total or 0) + 1
|
||||
tree = right
|
||||
end
|
||||
until not tree
|
||||
max = max or len(self)
|
||||
local to_visit = {tree}
|
||||
tree = nil
|
||||
local rank = min - 1
|
||||
local function next()
|
||||
if not tree then
|
||||
local len = #to_visit
|
||||
if len == 0 then return end
|
||||
tree = to_visit[len]
|
||||
to_visit[len] = nil
|
||||
else
|
||||
while tree.left do
|
||||
table.insert(to_visit, tree)
|
||||
tree = tree.left
|
||||
end
|
||||
end
|
||||
local key = tree.key
|
||||
tree = tree.right
|
||||
return key
|
||||
end
|
||||
return function()
|
||||
if rank >= max then
|
||||
return
|
||||
end
|
||||
local key = next()
|
||||
if key == nil then
|
||||
return
|
||||
end
|
||||
rank = rank + 1
|
||||
return rank, key
|
||||
end
|
||||
end
|
||||
|
||||
local function _right_rotation(parent, right, left)
|
||||
local new_parent = parent[left]
|
||||
parent[left] = new_parent[right]
|
||||
new_parent[right] = parent
|
||||
parent.total = (parent[left] and parent[left].total or 0) + (parent[right] and parent[right].total or 0) + 1
|
||||
assert(parent.total > 0 or (parent.left == nil and parent.right == nil))
|
||||
new_parent.total = (new_parent[left] and new_parent[left].total or 0) + parent.total + 1
|
||||
return new_parent
|
||||
end
|
||||
|
||||
local function right_rotation(parent)
|
||||
return _right_rotation(parent, "right", "left")
|
||||
end
|
||||
|
||||
local function left_rotation(parent)
|
||||
return _right_rotation(parent, "left", "right")
|
||||
end
|
||||
|
||||
local function _rebalance(parent)
|
||||
local left_count, right_count = (parent.left and parent.left.total or 0), (parent.right and parent.right.total or 0)
|
||||
if right_count > 1 and left_count * 2 < right_count then
|
||||
return left_rotation(parent)
|
||||
end
|
||||
if left_count > 1 and right_count * 2 < left_count then
|
||||
return right_rotation(parent)
|
||||
end
|
||||
return parent
|
||||
end
|
||||
|
||||
-- Rebalances a parent chain
|
||||
local function rebalance(self, len, parents, sides)
|
||||
if len <= 1 then
|
||||
return
|
||||
end
|
||||
for i = len, 2, -1 do
|
||||
parents[i] = _rebalance(parents[i])
|
||||
parents[i - 1][sides[i - 1]] = parents[i]
|
||||
end
|
||||
self.root = parents[1]
|
||||
end
|
||||
|
||||
local function _insert(self, key, replace)
|
||||
assert(key ~= nil)
|
||||
if is_empty(self) then
|
||||
self.root = {key = key, total = 1}
|
||||
return
|
||||
end
|
||||
local comparator = self.comparator
|
||||
local parents, sides = {}, {}
|
||||
local tree = self.root
|
||||
repeat
|
||||
local tree_key = tree.key
|
||||
local compared = comparator(key, tree_key)
|
||||
if compared == 0 then
|
||||
if replace then
|
||||
tree.key = key
|
||||
return tree_key
|
||||
end
|
||||
return
|
||||
end
|
||||
table.insert(parents, tree)
|
||||
local side = compared < 0 and "left" or "right"
|
||||
table.insert(sides, side)
|
||||
tree = tree[side]
|
||||
until not tree
|
||||
local len = #parents
|
||||
parents[len][sides[len]] = {key = key, total = 1}
|
||||
for _, parent in pairs(parents) do
|
||||
parent.total = parent.total + 1
|
||||
end
|
||||
rebalance(self, len, parents, sides)
|
||||
end
|
||||
|
||||
function insert(self, key)
|
||||
return _insert(self, key)
|
||||
end
|
||||
|
||||
function insert_or_replace(self, key)
|
||||
return _insert(self, key, true)
|
||||
end
|
||||
|
||||
local function _delete(self, key, is_rank)
|
||||
assert(key ~= nil)
|
||||
if is_empty(self) then
|
||||
return
|
||||
end
|
||||
local comparator = self.comparator
|
||||
local parents, sides = {}, {}
|
||||
local tree = self.root
|
||||
local rank = (tree.left and tree.left.total or 0) + 1
|
||||
repeat
|
||||
local tree_key = tree.key
|
||||
local compared
|
||||
if is_rank then
|
||||
if key == rank then
|
||||
compared = 0
|
||||
elseif key < rank then
|
||||
rank = rank - (tree.left and tree.left.right and tree.left.right.total or 0) - 1
|
||||
compared = -1
|
||||
else
|
||||
rank = rank + (tree.right and tree.right.left and tree.right.left.total or 0) + 1
|
||||
compared = 1
|
||||
end
|
||||
else
|
||||
compared = comparator(key, tree_key)
|
||||
end
|
||||
if compared == 0 then
|
||||
local len = #parents
|
||||
local left, right = tree.left, tree.right
|
||||
if left then
|
||||
tree.total = tree.total - 1
|
||||
if right then
|
||||
-- Obtain successor
|
||||
local side = left.total > right.total and "left" or "right"
|
||||
local other_side = side == "left" and "right" or "left"
|
||||
local sidemost = tree[side]
|
||||
while sidemost[other_side] do
|
||||
sidemost.total = sidemost.total - 1
|
||||
table.insert(parents, sidemost)
|
||||
table.insert(sides, other_side)
|
||||
sidemost = sidemost[other_side]
|
||||
end
|
||||
-- Replace deleted key
|
||||
tree.key = rightmost.key
|
||||
-- Replace the successor by it's single child
|
||||
parents[len][sides[len]] = sidemost[side]
|
||||
else
|
||||
if len == 0 then
|
||||
self.root = left or {total = 0}
|
||||
else
|
||||
parents[len][sides[len]] = left
|
||||
end
|
||||
end
|
||||
elseif right then
|
||||
if len == 0 then
|
||||
self.root = right or {total = 0}
|
||||
else
|
||||
tree.total = tree.total - 1
|
||||
parents[len][sides[len]] = right
|
||||
end
|
||||
else
|
||||
if len == 0 then
|
||||
self.root = {total = 0}
|
||||
else
|
||||
parents[len][sides[len]] = nil
|
||||
end
|
||||
end
|
||||
for _, parent in pairs(parents) do
|
||||
parent.total = parent.total - 1
|
||||
end
|
||||
rebalance(self, len, parents, sides)
|
||||
if is_rank then
|
||||
return tree_key
|
||||
end
|
||||
return rank, tree_key
|
||||
end
|
||||
table.insert(parents, tree)
|
||||
local side
|
||||
if compared < 0 then
|
||||
side = "left"
|
||||
else
|
||||
side = "right"
|
||||
end
|
||||
table.insert(sides, side)
|
||||
tree = tree[side]
|
||||
until not tree
|
||||
end
|
||||
|
||||
function delete(self, key)
|
||||
return _delete(self, key)
|
||||
end
|
||||
|
||||
delete_by_key = delete
|
||||
|
||||
function delete_by_rank(self, rank)
|
||||
return _delete(self, rank, true)
|
||||
end
|
||||
|
||||
--> `rank, key` if the key was found
|
||||
--> `rank` the key would have if inserted
|
||||
function get(self, key)
|
||||
if is_empty(self) then return end
|
||||
local comparator = self.comparator
|
||||
local tree = self.root
|
||||
local rank = (tree.left and tree.left.total or 0) + 1
|
||||
while tree do
|
||||
local compared = comparator(key, tree.key)
|
||||
if compared == 0 then
|
||||
return rank, tree.key
|
||||
end
|
||||
if compared < 0 then
|
||||
rank = rank - (tree.left and tree.left.right and tree.left.right.total or 0) - 1
|
||||
tree = tree.left
|
||||
else
|
||||
rank = rank + (tree.right and tree.right.left and tree.right.left.total or 0) + 1
|
||||
tree = tree.right
|
||||
end
|
||||
end
|
||||
return rank
|
||||
end
|
||||
|
||||
get_by_key = get
|
||||
|
||||
--> key
|
||||
function get_by_rank(self, rank)
|
||||
local tree = self.root
|
||||
local current_rank = (tree.left and tree.left.total or 0) + 1
|
||||
repeat
|
||||
if rank == current_rank then
|
||||
return tree.key
|
||||
end
|
||||
local left, right = tree.left, tree.right
|
||||
if rank < current_rank then
|
||||
current_rank = current_rank - (left and left.right and left.right.total or 0) - 1
|
||||
tree = left
|
||||
else
|
||||
current_rank = current_rank + (right and right.left and right.left.total or 0) + 1
|
||||
tree = right
|
||||
end
|
||||
until not tree
|
||||
end
|
43
test.lua
43
test.lua
@ -47,6 +47,49 @@ do
|
||||
end
|
||||
end
|
||||
|
||||
-- ranked set
|
||||
do
|
||||
local n = 100
|
||||
local ranked_set = modlib.ranked_set.new()
|
||||
local list = {}
|
||||
for i = 1, n do
|
||||
ranked_set:insert(i)
|
||||
list[i] = i
|
||||
end
|
||||
|
||||
assert(modlib.table.equals(ranked_set:to_table(), list))
|
||||
|
||||
local i = 0
|
||||
for rank, key in ranked_set:ipairs() do
|
||||
i = i + 1
|
||||
assert(i == key and i == rank)
|
||||
assert(ranked_set:get_by_rank(rank) == key)
|
||||
local rank, key = ranked_set:get(i)
|
||||
assert(key == i and i == rank)
|
||||
end
|
||||
assert(i == n)
|
||||
|
||||
for i = 1, n do
|
||||
local _, v = ranked_set:delete(i)
|
||||
assert(v == i, i)
|
||||
end
|
||||
assert(not next(ranked_set:to_table()))
|
||||
|
||||
local ranked_set = modlib.ranked_set.new()
|
||||
for i = 1, n do
|
||||
ranked_set:insert(i)
|
||||
end
|
||||
|
||||
for rank, key in ranked_set:ipairs(10, 20) do
|
||||
assert(rank == key and key >= 10 and key <= 20)
|
||||
end
|
||||
|
||||
for i = n, 1, -1 do
|
||||
local j = ranked_set:delete_by_rank(i)
|
||||
assert(j == i)
|
||||
end
|
||||
end
|
||||
|
||||
-- in-game tests
|
||||
local tests = {
|
||||
liquid_dir = false,
|
||||
|
Loading…
Reference in New Issue
Block a user