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@mrchaofan
Created May 6, 2023 07:54
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/**
* @typedef {{
* value: number
* left: BSTreeNode
* right: BSTreeNode
* }} BSTreeNode
*/
class BSTree {
/**
*
* @param { BSTreeNode } node
* @param {number} value
*/
static insert(node, value) {
if (node == null) {
return {
value,
left: null,
right: null
}
}
if (value < node.value) {
node.left = this.insert(node.left, value)
} else if (value > node.value) {
node.right = this.insert(node.right, value)
}
return node
}
/**
*
* @param {BSTreeNode} node
* @param {number} lo
* @param {number} hi
* @param {number[]} results
*/
static range(node, lo, hi, results) {
if (node == null) {
return
}
if (lo < node.value) {
this.range(node.left, lo, hi, results)
}
if (lo <= node.value && hi > node.value) {
results.push(node.value)
}
if (hi > node.value) {
this.range(node.right, lo, hi, results)
}
}
/**
*
* @param {BSTreeNode} node
* @param {any}value
*/
static floor(node, value) {
if (node == null) {
return
}
if (value >= node.value) {
return this.floor(node.right, value) ?? node.value
}
return this.floor(node.left, value)
}
/**
*
* @param { BSTreeNode }node
* @param {any} value
*/
static ceil(node, value) {
if (node == null) {
return
}
if (value <= node.value) {
return this.ceil(node.left, value) ?? node.value
}
return this.ceil(node.right, value)
}
/**
*
* @param {BSTreeNode} node
* @param {*} value
* @param {*} ctx
*/
static delete(node, value, ctx) {
if (node != null) {
ctx.lastSeen = node
if (value < node.value) {
node.left = this.delete(node.left, value, ctx)
} else {
ctx.delete = node
node.right = this.delete(node.right, value, ctx)
}
if (ctx.lastSeen === node) {
if (ctx.delete && ctx.delete.value === value) {
ctx.delete.value = node.value
return node.right
}
}
}
return node
}
constructor() {
/**
* @type {BSTreeNode}
*/
this.root = null
}
/**
*
* @param {number} value
*/
insert(value) {
return this.root = BSTree.insert(this.root, value)
}
/**
*
* @param {number} lo
* @param {number} hi
*/
range(lo, hi) {
const results = []
BSTree.range(this.root, lo, hi, results)
return results
}
/**
*
* @param {any} value
*/
floor(value) {
return BSTree.floor(this.root, value)
}
/**
*
* @param {any} value
*/
ceil(value) {
return BSTree.ceil(this.root, value)
}
/**
*
* @param {*} value
*/
delete(value) {
return BSTree.delete(this.root, value, {})
}
}
const bstree = new BSTree()
bstree.insert(6)
bstree.insert(7)
bstree.insert(2)
bstree.insert(1)
bstree.insert(5)
bstree.insert(3)
bstree.insert(4)
bstree.range(3, 6)
bstree.floor(3)
bstree.ceil(3)
bstree.delete(2)
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