Java 用字符串方法导出多项式

有一个来自用户的输入字符串。这是一个多项式。如果不使用数组，如何导出此polinom

ınput=3x^4+5x^45-2+77x^100

输出必须为12x^3+225x^44+7700x^99

我怎么知道多项式中有多少个x语句

我的代码是：

String katsayi = polinom.substring(0, polinom.indexOf("x"));
String us = polinom.substring(a + 1);
int katSayi = Integer.parseInt(katsayi);
int uS = Integer.parseInt(us);
katSayi = katSayi * uS;
uS = uS - 1;
katsayi = Integer.toString(katSayi);
us = Integer.toString(uS);
yeniPolinom = katsayi + "x^" + us;
System.out.println(yeniPolinom);

---

解析一个看起来像多项式的字符串可能非常乏味，因为有数百种方法可以写下同一个多项式。但是，如果我们坚持使用ax^n格式，您可以查看此答案以提取多项式的系数：

考虑使用导数方法创建一个多项式类。

如何使用正则表达式查找[number1]x^[number2]格式的部分，然后用[num1]*[num2]x^[numm2-1]替换这些部分？下面是一个基于找到的值动态创建替换零件的示例

String input = "3x^4+5x^45-2+77x^100";

Pattern p = Pattern.compile("(\\d+)x\\^(\\d+)");
//                            ^^^^      ^^^^
//                           group1    group2
Matcher m = p.matcher(input);
StringBuffer sb = new StringBuffer();
while (m.find()) {
    int a = Integer.parseInt(m.group(1));
    int n = Integer.parseInt(m.group(2));
    if (n != 0)
        m.appendReplacement(sb, (a * n) + "x^" + (n - 1));
    else
        m.appendReplacement(sb, "0");
}
m.appendTail(sb);
String output = sb.toString();
System.out.println(output);

输出：12x^3+225x^44-2+7700x^99

---

请注意，此解决方案非常有限。它假定所有部分都将以ax^n形式写入，因此对于诸如x^2而不是1x^2，或-1而不是-1x^0之类的数据，它将无法正常工作。我还假设n不是负数

你想得到导数吗？是的，但我会从用户那里得到innput字符串@BRSO05给我一点时间，我将尝试为您整理一个答案…用户将编写输入。因此，输入可以有许多x语句。我们不知道。我试图得到这个输入的导数。如果是3x^2+2x^33，则输出将是6x+66x@BRSO05所有部分是否都以ax^n的形式写入，或者输入是否可以像x^2一样写入而不是像1x^2一样写入，或者不可以像1一样写入x部分而不是像1x^0一样写入？

 public static void main(String[] args) throws IOException {
        String polynomial = "3x^4+5x^45-2+77x^100";
        int lastNumber = 0;
        int temp = 0;
        String output = "";
        for(int i = 0; i < polynomial.length() - 1; i++)
        {
            if(polynomial.charAt(i) == 'x')
            {
                int counter = i + 1;
                int a = 0;
                int b = 0;
                String tempString1 = "";
                String tempString2 = "";
                String number = "";
                while((polynomial.charAt(counter) != '0') && (polynomial.charAt(counter) != '1') && (polynomial.charAt(counter) != '2') && (polynomial.charAt(counter) != '3') && (polynomial.charAt(counter) != '4') && (polynomial.charAt(counter) != '5') && (polynomial.charAt(counter) != '6') && (polynomial.charAt(counter) != '7') && (polynomial.charAt(counter) != '8') && (polynomial.charAt(counter) != '9'))
                {
                    tempString1 += polynomial.charAt(counter);
                    counter++;
                }
                while((counter < polynomial.length()) && ((polynomial.charAt(counter) == '0') || (polynomial.charAt(counter) == '1') || (polynomial.charAt(counter) == '2') || (polynomial.charAt(counter) == '3') || (polynomial.charAt(counter) == '4') || (polynomial.charAt(counter) == '5') || (polynomial.charAt(counter) == '6') || (polynomial.charAt(counter) == '7') || (polynomial.charAt(counter) == '8') || (polynomial.charAt(counter) == '9')))
                {
                    number += polynomial.charAt(counter);
                    counter++;
                }
                a = Integer.parseInt(number);
                temp = counter - 1;
                counter = i - 1;
                number = "";
                while((polynomial.charAt(counter) != '0') && (polynomial.charAt(counter) != '1') && (polynomial.charAt(counter) != '2') && (polynomial.charAt(counter) != '3') && (polynomial.charAt(counter) != '4') && (polynomial.charAt(counter) != '5') && (polynomial.charAt(counter) != '6') && (polynomial.charAt(counter) != '7') && (polynomial.charAt(counter) != '8') && (polynomial.charAt(counter) != '9'))
                {
                    tempString2 = polynomial.charAt(counter) + tempString2;
                    counter--;
                }
                while((counter >= 0) && ((polynomial.charAt(counter) == '0') || (polynomial.charAt(counter) == '1') || (polynomial.charAt(counter) == '2') || (polynomial.charAt(counter) == '3') || (polynomial.charAt(counter) == '4') || (polynomial.charAt(counter) == '5') || (polynomial.charAt(counter) == '6') || (polynomial.charAt(counter) == '7') || (polynomial.charAt(counter) == '8') || (polynomial.charAt(counter) == '9')))
                {
                    number = polynomial.charAt(counter) + number;
                    counter--;
                }
                b = Integer.parseInt(number);
                for(int j = lastNumber; j <= counter; j++)
                {
                    output += polynomial.charAt(j);
                }
                output += "" + (a * b) + "x^" + (a - 1);
                lastNumber = temp + 1;
                i = temp;
            }
        }
        System.out.println(output);
    }

12x^3+225x^44-2+7700x^99