SOURCE

function Stack(){
    this.dataStore = [];
    this.top = 0;
    this.push = push;
    this.pop = pop;
    this.peek = peek;
    this.clear = clear;
    this.length = length;
}

function push(element){
    this.dataStore[this.top++] = element;
}

function pop(){
    return this.dataStore[--this.top];
    
}

function peek(){
    return this.dataStore[this.top-1];
}

function clear(){
    this.top = 0;
}

function length(){
    return this.top;
}

//一、数字n转换为以b（2-9）为基数的数字
// 1.最高位为n%b,压入栈
// 2.使用n/b代替n
// 3.重复1.2.，直到n等于0，且没有余数
// 4.持续将栈内元素弹出，直到栈为空，元素依次排列，得到转换后数字的字符串形式

function mulBase(num,base){
    var s = new Stack();
    do{
        s.push(num%base);
        num = Math.floor(num /= base);
    }while(num>0);

    var converted = '';
    while(s.length()>0){
        converted += s.pop();
    }
    return converted;
}

var num = 32;
var base = 2;
var newNum = mulBase(num,base);
console.log(newNum)


// 二.回文  1001  racecar
function isPalindrome(word){
    var a = new Stack();
    for(var i = 0;i<word.length;i++){
        a.push(word[i]);
    }
    var rword = '';
    while(a.length()>0){
        rword += a.pop();
    }
    if(word ==rword){
        return true;
    }
    else{
        return false; 
    }
}

var word = 'hello';
if(isPalindrome(word)){
    console.log(word + ' is a palindrome');
}else{
     console.log(word + ' is not a palindrome');
}

word = 'racecar';
if(isPalindrome(word)){
    console.log(word + ' is a palindrome');
}else{
     console.log(word + ' is not a palindrome');
}

// 三.实现括号匹配 返回括号缺失位置

// 使用用两个栈，一个存储所有字符，一个只存储括号
// s1入栈所有字符
// 而遇到前括号，入栈s2；遇到后括号，查看s2最顶部的括号是否匹配
// 若匹配则让s2出栈该后括号匹配的前括号，即最顶部的括号
// 若不匹配，则返回括号不匹配或缺失的位置

function isMatch(str){
    const s1 = new Stack();
    const s2 = new Stack();
    let num = '';
    const sign1 = '+-*/()[]{}';
    const sign2 = '()[]{}';

    for(var i = 0;i<str.length;i++){
        if(sign2.indexOf(str[i]) > -1){
            switch(str[i]){
                case'(':
                case'[':
                case'{':s2.push(str[i]);break;

                 case')':
                         if(s2.peek() != "("){
                             return `在${s1.peek()}后不匹配`
                         };
                         s2.pop();
                         break;
                case']':
                        if(s2.peek() != "["){
                             return `在${s1.peek()}后不匹配`
                         };
                         s2.pop();
                         break;
                case'}':
                        if(s2.peek() != "{"){
                             return `在${s1.peek()}后不匹配`
                         };
                         s2.pop();
                         break;

            }
        }
        if(sign1.indexOf(str[i])>-1){
            s1.push(str[i]);
            continue;
        }
        while('0'<= str[i] && str[i] <= '9' || str[i] == '.'){
            num += str[i];
            i++
        }
        i--;
        s1.push(num);
        num='';
    }
    return s2.length() > 0 ? `在末尾，${s1.peek()}后不匹配` : '匹配';
}