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This article mainly introduces you to the relevant information about deduplication and optimization of numerical arrays using js to build binary trees. The article introduces it in great detail through sample codes. It has certain reference learning value for everyone's study or work. It needs Friends, let’s study together.
Preface
This article mainly introduces the relevant content about constructing a binary tree with js to deduplicate and optimize numerical arrays. It is shared for your reference. Learning, I won’t say much more below, let’s take a look at the detailed introduction.
Common two-layer loop to implement array deduplication
##
let arr = [11, 12, 13, 9, 8, 7, 0, 1, 2, 2, 5, 7, 11, 11, 7, 6, 4, 5, 2, 2] let newArr = [] for (let i = 0; i < arr.length; i++) { let unique = true for (let j = 0; j < newArr.length; j++) { if (newArr[j] === arr[i]) { unique = false break } } if (unique) { newArr.push(arr[i]) } } console.log(newArr)
Construct a binary tree to achieve deduplication (only applicable to numeric type arrays)
let arr = [0, 1, 2, 2, 5, 7, 11, 7, 6, 4,5, 2, 2] class Node { constructor(value) { this.value = value this.left = null this.right = null } } class BinaryTree { constructor() { this.root = null this.arr = [] } insert(value) { let node = new Node(value) if (!this.root) { this.root = node this.arr.push(value) return this.arr } let current = this.root while (true) { if (value > current.value) { if (current.right) { current = current.right } else { current.right = node this.arr.push(value) break } } if (value < current.value) { if (current.left) { current = current.left } else { current.left = node this.arr.push(value) break } } if (value === current.value) { break } } return this.arr } } let binaryTree = new BinaryTree() for (let i = 0; i < arr.length; i++) { binaryTree.insert(arr[i]) } console.log(binaryTree.arr)
Optimization idea one, record the maximum and minimum values
let arr = [11, 12, 13, 9, 8, 7, 0, 1, 2, 2, 5, 7, 11, 11, 7, 6, 4, 5, 2, 2] class Node { constructor(value) { this.value = value this.left = null this.right = null } } class BinaryTree { constructor() { this.root = null this.arr = [] this.max = null this.min = null } insert(value) { let node = new Node(value) if (!this.root) { this.root = node this.arr.push(value) this.max = value this.min = value return this.arr } if (value > this.max) { this.arr.push(value) this.max = value this.findMax().right = node return this.arr } if (value < this.min) { this.arr.push(value) this.min = value this.findMin().left = node return this.arr } let current = this.root while (true) { if (value > current.value) { if (current.right) { current = current.right } else { current.right = node this.arr.push(value) break } } if (value < current.value) { if (current.left) { current = current.left } else { current.left = node this.arr.push(value) break } } if (value === current.value) { break } } return this.arr } findMax() { let current = this.root while (current.right) { current = current.right } return current } findMin() { let current = this.root while (current.left) { current = current.left } return current } } let binaryTree = new BinaryTree() for (let i = 0; i < arr.length; i++) { binaryTree.insert(arr[i]) } console.log(binaryTree.arr)
##Optimization Idea 2, build a red-black tree
Build a red-black tree and balance the height of the tree
For the red-black tree, please see the red-black tree Insert
let arr = [11, 12, 13, 9, 8, 7, 0, 1, 2, 2, 5, 7, 11, 11, 7, 6, 4, 5, 2, 2] console.log(Array.from(new Set(arr))) class Node { constructor(value) { this.value = value this.left = null this.right = null this.parent = null this.color = 'red' } } class RedBlackTree { constructor() { this.root = null this.arr = [] } insert(value) { let node = new Node(value) if (!this.root) { node.color = 'black' this.root = node this.arr.push(value) return this } let cur = this.root let inserted = false while (true) { if (value > cur.value) { if (cur.right) { cur = cur.right } else { cur.right = node this.arr.push(value) node.parent = cur inserted = true break } } if (value < cur.value) { if (cur.left) { cur = cur.left } else { cur.left = node this.arr.push(value) node.parent = cur inserted = true break } } if (value === cur.value) { break } } // 调整树的结构 if(inserted){ this.fixTree(node) } return this } fixTree(node) { if (!node.parent) { node.color = 'black' this.root = node return } if (node.parent.color === 'black') { return } let son = node let father = node.parent let grandFather = father.parent let directionFtoG = father === grandFather.left ? 'left' : 'right' let uncle = grandFather[directionFtoG === 'left' ? 'right' : 'left'] let directionStoF = son === father.left ? 'left' : 'right' if (!uncle || uncle.color === 'black') { if (directionFtoG === directionStoF) { if (grandFather.parent) { grandFather.parent[grandFather.parent.left === grandFather ? 'left' : 'right'] = father father.parent = grandFather.parent } else { this.root = father father.parent = null } father.color = 'black' grandFather.color = 'red' father[father.left === son ? 'right' : 'left'] && (father[father.left === son ? 'right' : 'left'].parent = grandFather) grandFather[grandFather.left === father ? 'left' : 'right'] = father[father.left === son ? 'right' : 'left'] father[father.left === son ? 'right' : 'left'] = grandFather grandFather.parent = father return } else { grandFather[directionFtoG] = son son.parent = grandFather son[directionFtoG] && (son[directionFtoG].parent = father) father[directionStoF] = son[directionFtoG] father.parent = son son[directionFtoG] = father this.fixTree(father) } } else { father.color = 'black' uncle.color = 'black' grandFather.color = 'red' this.fixTree(grandFather) } } } let redBlackTree = new RedBlackTree() for (let i = 0; i < arr.length; i++) { redBlackTree.insert(arr[i]) } console.log(redBlackTree.arr)
Other deduplication methods
[...new Set(arr)]
Deduplication through
sort() reduce()
method
After sorting, compare adjacent elements to see if they are the same. If they are different, add them to the returned array.
It is worth noting that when sorting, the default
compare(2, '2')Return 0; while reduce(), perform congruent comparison
let arr = [0, 1, 2, '2', 2, 5, 7, 11, 7, 5, 2, '2', 2] let newArr = [] arr.sort((a, b) => { let res = a - b if (res !== 0) { return res } else { if (a === b) { return 0 } else { if (typeof a === 'number') { return -1 } else { return 1 } } } }).reduce((pre, cur) => { if (pre !== cur) { newArr.push(cur) return cur } return pre }, null)
Through
includes() map()
Method to remove duplicates
let arr = [0, 1, 2, '2', 2, 5, 7, 11, 7, 5, 2, '2', 2] let newArr = [] arr.map(a => !newArr.includes(a) && newArr.push(a))
By
includes() reduce()
Method to remove duplicates
let arr = [0, 1, 2, '2', 2, 5, 7, 11, 7, 5, 2, '2', 2] let newArr = arr.reduce((pre, cur) => { !pre.includes(cur) && pre.push(cur) return pre }, [])
Deduplicate the JSON object through the key value of the object
let arr = [0, 1, 2, '2', 2, 5, 7, 11, 7, 5, 2, '2', 2] let obj = {} arr.map(a => { if(!obj[JSON.stringify(a)]){ obj[JSON.stringify(a)] = 1 } }) console.log(Object.keys(obj).map(a => JSON.parse(a)))
The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.
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