Vasya - Clerk

题目

he new “Avengers” movie has just been released! There are a lot of people at the cinema box office standing in a huge line. Each of them has a single 100, 50 or 25 dollar bill. An “Avengers” ticket costs 25 dollars.

Vasya is currently working as a clerk. He wants to sell a ticket to every single person in this line.

Can Vasya sell a ticket to every person and give change if he initially has no money and sells the tickets strictly in the order people queue?

Return YES, if Vasya can sell a ticket to every person and give change with the bills he has at hand at that moment. Otherwise return NO.

Examples:

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tickets([25, 25, 50]) // => YES 
tickets([25, 100]) // => NO. Vasya will not have enough money to give change to 100 dollars
tickets([25, 25, 50, 50, 100]) // => NO. Vasya will not have the right bills to give 75 dollars of change (you can't make two bills of 25 from one of 50)

思路

很菜，用的多重判断。需要注意以下几点：

  • 仅仅是数值上够的话是不行的，首先要注意自己手里的钞票够不够用
  • 优先使用50的钞票，否则会出现明明够但是返回NO的情况

答案

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function tickets(peopleInLine) {
    console.log(peopleInLine)
    var notes = {'25': 0, '50': 0, '100': 0};
    for (var i in peopleInLine) {
        if (peopleInLine[i] === 25) {
            notes['25'] += 1;
        } else if (peopleInLine[i] === 50) {
            if (notes['25'] > 0) {
                notes['50'] += 1;
                notes['25'] -= 1;
            } else {
                return 'NO';
            }
        } else {
            if (notes['50'] > 0 && notes['25'] > 0) {
                notes['25'] -= 1;
                notes['50'] -= 1;
                notes['100'] += 1;

            } else if (notes['25'] > 2) {
                notes['25'] -= 3;
                notes['100'] += 1;
            } else {
                return 'NO';
            }
        }
    }
    return "YES";
}