[IT技術30篇挑戰] 資料結構和演算法實作 DAY3

章節連結

指令
LeetCode 練習記錄
系列文章

堆疊式一個遵循LIFO(Left In First Out)後進先出的原則。在現實中就有點像是堆在桌上的書，越上方的(後放)會越先被拿走。不過 JavaScript 並沒有內建這樣的資料結構，但可以用 array 陣列的方法來達成。

指令

/*Stack*/
function Stack(){
	var items = []
	this.push = function(element){
		return items.push(element)
	}
	this.pop = function(){
		return items.pop()
	}
	this.peek = function(){
		return items[items.length-1]
	}
	this.isEmpty = function(){
		return items.length === 0
	}
	this.size = function(){
		return items.length
	}
	this.clear = function(){
		return items = []
	}
	this.print = function(){
		console.log(items.toString())
	}
}

// 10 進位轉 2 進位
function decTobin(decNum){
	let stack = new Stack()
	let temp = 0
	let binary = ''
	while(decNum>0){
		temp = Math.floor(decNum%2)
		stack.push(temp)
		decNum = Math.floor(decNum/2)
	}
	while(!stack.isEmpty()){
		binary += stack.pop().toString()
	}
	return binary
}

// 10 進位轉 N 進位 (最多到16進位)
function baseConverter(decNum, base){
	let stack = new Stack()
	let temp = 0
	let result = ''
	let digits = '0123456789ABCDEF'
	while(decNum>0){
		temp = Math.floor(decNum%base)
		stack.push(temp)
		decNum = Math.floor(decNum/base)
	}
	while(!stack.isEmpty()){
		result += digits[stack.pop()]
	}
	return result
}

console.log(baseConverter(100,2))
console.log(baseConverter(100,4))
console.log(baseConverter(100,8))
console.log(baseConverter(100,10))
console.log(baseConverter(100,16))

/*Stack*/

function Stack(){

var items = []

this.push = function(element){

return items.push(element)

}

this.pop = function(){

return items.pop()

}

this.peek = function(){

return items[items.length-1]

}

this.isEmpty = function(){

return items.length === 0

}

this.size = function(){

return items.length

}

this.clear = function(){

return items = []

}

this.print = function(){

console.log(items.toString())

}

// 10 進位轉 2 進位

function decTobin(decNum){

let stack = new Stack()

let temp = 0

let binary = ''

while(decNum>0){

temp = Math.floor(decNum%2)

stack.push(temp)

decNum = Math.floor(decNum/2)

}

while(!stack.isEmpty()){

binary += stack.pop().toString()

}

return binary

}

// 10 進位轉 N 進位 (最多到16進位)

function baseConverter(decNum, base){

let stack = new Stack()

let temp = 0

let result = ''

let digits = '0123456789ABCDEF'

while(decNum>0){

temp = Math.floor(decNum%base)

stack.push(temp)

decNum = Math.floor(decNum/base)

}

while(!stack.isEmpty()){

result += digits[stack.pop()]

}

return result

}

console.log(baseConverter(100,2))

console.log(baseConverter(100,4))

console.log(baseConverter(100,8))

console.log(baseConverter(100,10))

console.log(baseConverter(100,16))

LeetCode 練習記錄

// 225. Implement Stack using Queues https://leetcode.com/problems/implement-stack-using-queues/
var MyStack = function() {
    items = []
};

MyStack.prototype.push = function(x) {
    return items.push(x)
};

MyStack.prototype.pop = function() {
    return items.pop()
};

MyStack.prototype.top = function() {
    return items[items.length-1]
};

MyStack.prototype.empty = function() {
   return items.length === 0 ? true : false
};

/** 
 * Your MyStack object will be instantiated and called as such:
 * var obj = new MyStack()
 * obj.push(x)
 * var param_2 = obj.pop()
 * var param_3 = obj.top()
 * var param_4 = obj.empty()
 */