简单零钱制作程序中奇怪的计数行为
简单零钱制作程序中奇怪的计数行为
提问于 2019-04-17 15:21:11
因此，我制作了一个相当简单的最优更改程序，它在大多数情况下都工作得很好。但出于某种奇怪的原因，它表现得不一致，有时不会添加所需的最后一分钱，但有时它会。
我尝试了不同的输出，代码总是正确的，除非有时是最后一分钱；当使用美国货币时。我相信原因是显而易见的，但我就是看不出来。
public static int[] optimal_change(double[] currency, double amount) {
int[] count = new int[currency.length];
for (int i = 0; i < currency.length; i++) {
if (amount >= currency[i]) {
amount -= currency[i];
count[i]++;
i--;
}
if (amount == 0.0000) {
break;
}
}
return count;
}public static void main(String[] args) {
double[] american_currency = {100,50,20,10,5,1,0.25,0.10,0.05,0.01};
//Japanese currency: https://www.boj.or.jp/en/note_tfjgs/note/valid/index.htm/
double[] japanese_currency = {10000,5000,2000,1000,500,100,50,10,5,1};
int[] american_change = optimal_change(american_currency, 78.36);
int[] japanese_change = optimal_change(japanese_currency, 793048);
System.out.println("Optimal change for: $78.38");
for (int i = 0; i < american_currency.length; i++) {
if (i <= 5) {
System.out.println(Integer.toString(american_change[i]) + " $" + Double.toString(american_currency[i]));
} else {
System.out.println(Integer.toString(american_change[i]) + " " + Double.toString(american_currency[i]) + "¢");
}
}
System.out.println("--------------------------");
System.out.println("Optimal change for: ¥793040");
for (int i = 0; i < japanese_currency.length; i++) {
System.out.println(Integer.toString(japanese_change[i]) + " ¥" + Double.toString(japanese_currency[i]));
}
}正确的结果：
输入: 78.37
输出：
最优变化:78.37美元
0 $100.0
1 $50.0
1 $20.0
0 $10.0
1 $5.0
3美元1.0美元
1 0.25美分
1 0.1欧
0 0.05？
2 0.01美分
错误的结果：
输入: 78.38
输出：
最优变化:78.38美元
0 $100.0
1 $50.0
1 $20.0
0 $10.0
1 $5.0
3美元1.0美元
1 0.25美分
1 0.1欧
0 0.05？
2 0.01美分
输出应该是：
最优变化:78.38美元
0 $100.0
1 $50.0
1 $20.0
0 $10.0
1 $5.0
3美元1.0美元
1 0.25美分
1 0.1欧
0 0.05？
3 0.01美分
回答 2
Stack Overflow用户
回答已采纳
发布于 2019-04-18 08:39:34
切换到BigDecimal似乎解决了这个问题。不确定为什么替身的问题会持续这么长时间。但值得庆幸的是，它起作用了。
import java.math.BigDecimal;
public class Greedy_Money_BigInteger {
public static int[] optimal_change(BigDecimal[] currency, BigDecimal amount) {
int[] count = new int[currency.length];
for (int i = 0; i < currency.length; i++) {
//if (amount >= currency[i]) {
if (amount.compareTo(currency[i]) >= 0) {
amount = amount.subtract(currency[i]);
count[i]++;
i--;
}
if (amount.compareTo(BigDecimal.valueOf(0)) <= 0) {
break;
}
}
return count;
}
public static void main(String[] args) {
BigDecimal[] american_currency = {BigDecimal.valueOf(100),BigDecimal.valueOf(50),BigDecimal.valueOf(20),BigDecimal.valueOf(10),BigDecimal.valueOf(5),BigDecimal.valueOf(1),BigDecimal.valueOf(0.25),BigDecimal.valueOf(0.10),BigDecimal.valueOf(0.05),BigDecimal.valueOf(0.01)};
//Japanese currency: https://www.boj.or.jp/en/note_tfjgs/note/valid/index.htm/
BigDecimal[] japanese_currency = {BigDecimal.valueOf(10000),BigDecimal.valueOf(5000),BigDecimal.valueOf(2000),BigDecimal.valueOf(1000),BigDecimal.valueOf(500),BigDecimal.valueOf(100),BigDecimal.valueOf(50),BigDecimal.valueOf(10),BigDecimal.valueOf(5),BigDecimal.valueOf(1)};
BigDecimal american_change_value = BigDecimal.valueOf(78.31);
BigDecimal japanese_change_value = BigDecimal.valueOf(793043);
int[] american_change = optimal_change(american_currency, american_change_value);
int[] japanese_change = optimal_change(japanese_currency, japanese_change_value);
System.out.println("Optimal change for: $" + american_change_value.toString());
for (int i = 0; i < american_currency.length; i++) {
if (american_change[i] > 0) {
if (i <= 5) {
System.out.println(Integer.toString(american_change[i]) + " $" + american_currency[i].toString());
} else {
System.out.println(Integer.toString(american_change[i]) + " " + american_currency[i].toString() + "¢");
}
}
}
System.out.println("--------------------------");
System.out.println("Optimal change for: ¥" + japanese_change_value.toString());
for (int i = 0; i < japanese_currency.length; i++) {
if (japanese_change[i] > 0) {
System.out.println(Integer.toString(japanese_change[i]) + " ¥" + japanese_currency[i].toString());
}
}
}
}Stack Overflow用户
发布于 2019-04-17 15:40:43
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/55722017
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