Question

这是问题陈述，

你有很多带有出发地和目的地的门票。您获得了出发城市和目的地城市。你怎么能从堆栈中找到你的路线。这是我的解决方案，

"use strict";


function app(){

    var stack = [];
    var one = new Ticket('London', 'NYC');
    var two = new Ticket('Barcelona', 'Athens');
    var three = new Ticket('Rio', 'ND');
    var four = new Ticket('NYC', 'Barcelona');
    var five = new Ticket('Athens', 'Rio');
    var six = new Ticket('ND', "Lahore");
    stack.push(one);
    stack.push(two);
    stack.push(three);
    stack.push(four);
    stack.push(five);
    stack.push(six);

    var res = sortDestinations(stack, 'London', 'Lahore');
    for(var city in res){
        console.out(res[city]);
    }

}
function Ticket(departure, destination){

    this.departure = departure;
    this.destination = destination;
}

Ticket.prototype.getDeparture = function(){
    return this.departure;
}

Ticket.prototype.getDestination = function(){
    return this.destination;
}


function sortDestinations(stack, dep, dest){
    var map = {};
    for(var i= 0; i<stack.length; i++){
        var ticket = stack.pop();
        map[ticket.getDeparture()] = ticket.getDestination();
    }
    var res = [];
    var curr = dep;
    res.push(curr);

    while(true){
        if(curr == dest) {
            break;
        }
        var next = map[curr];
        res.push(next);
        curr = next;
    }

}

app();

这个程序进入无限循环。当我调试时，我看到curr变量未定义。有人可以帮我解决问题。我是Javascript的新手。

Answer 1

我正在调试您的代码一段时间，最后确定了infinite loop的原因。由于pop来自stack，stack的长度不断减少，i的长度增加，循环在完成前停止。并且while循环保持循环，因为curr永远不会等于dept，因为map不包含London。

更改此

for(var i= 0; i<stack.length; i++){
    var ticket = stack.pop();
    map[ticket.getDeparture()] = ticket.getDestination();
}

到

while(stack.length>0){
    var ticket = stack.pop();
    map[ticket.getDeparture()] = ticket.getDestination();
}

排序一系列门票

1 个答案: