超大非负数求和

最新推荐文章于 2021-07-16 19:53:10 发布

wangff_187

最新推荐文章于 2021-07-16 19:53:10 发布

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分类专栏：算法文章标签：超大数求和 java

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<code>

package Demo;

import java.util.Arrays;

public class StringDemo {

   public static String add(String num1, String num2){
   //第一个数整数部分
       String num1zs = "";
       //第一个数小数部分
       String num1xs = "";
       //第2个数整数部分
       String num2zs = "";
       //第2个数小数部分
       String num2xs = "";
       int nsum = 0;
       int nOverToken = 0;
       //处理输入
       if(num1.indexOf(".") > 0){
           System.out.println(num1);
           String[] num1Arr = num1.split("\\.");
           System.out.println(Arrays.toString(num1Arr)+ "***");
           num1zs = num1Arr[0];
           num1xs = num1Arr[1];
       }else{
           num1zs = num1;
       }
       if(num2.indexOf(".") > 0){
           String[] num2Arr = num2.split("\\.");
           num2zs = num2Arr[0];
           num2xs = num2Arr[1];
       }else{
           num2zs = num2;
       }
       System.out.println("num1整数部分 :" + num1zs + " num2整数部分:" + num2zs + " num1小数部分 :" + num1xs + " num2小数部分:" + num2xs);
       //先计算小数部分
       int length1xs = num1xs.length();
       int length2xs = num2xs.length();
       int blenx = length1xs >= length2xs ? length1xs : length2xs;
       int slenx = length1xs >= length2xs ? length2xs : length1xs;
       String numx = length1xs >= length2xs ? num1xs : num2xs;
       //用来承载小数部分加法之后的结果
       StringBuilder numxBuilder = new StringBuilder(numx);
       for(int i = blenx-1; i >=0; i--){
           if(i < slenx){
               nsum = num1xs.charAt(i) - '0' + num2xs.charAt(i) - '0' + nOverToken;
               if(nsum >= 10){
                   nsum-=10;
                   nOverToken = 1;
                   numxBuilder.setCharAt(i, (char)(nsum + '0'));
               }
               else{
                   numxBuilder.setCharAt(i, (char)(nsum + '0'));
                   nOverToken = 0;
               }
           }
       }
       //若小数部分尾部'0',则将0去掉
       for(int j = numxBuilder.length()-1; j >=0; j--){
           if (!(numxBuilder.charAt(j) == '0')) {
               break;
           }
           numxBuilder.deleteCharAt(j);
       }

       //处理整数部分
       int length1zs = num1zs.length();
       int length2zs = num2zs.length();
       int zsLengthDiff = Math.abs(length1zs - length2zs);
       //将整数位小的前面补"0"处理,并且用来承载整数部分加法之后的结果
       StringBuilder builder = new StringBuilder();
       for(int j=0; j <zsLengthDiff; j++ ){
           builder.append("0");
       }
       String numzlengthLittle = length1zs >= length2zs ? num2zs : num1zs;
       builder.append(numzlengthLittle);
       String numz = length1zs >= length2zs ? num1zs : num2zs;
//       System.out.println(builder.length());
//       System.out.println(numz.length());
       for(int i = builder.length() - 1; i >=0; i--){
           nsum = builder.charAt(i) - '0' + numz.charAt(i) - '0' + nOverToken;
           if(nsum >= 10){
               nsum-=10;
               nOverToken = 1;
               builder.setCharAt(i, (char)(nsum + '0'));
           }else{
               builder.setCharAt(i, (char)(nsum + '0'));
               nOverToken = 0;
           }
       }
       if(!numxBuilder.toString().equals("")){
           if(nOverToken == 1){
               return "1" + builder.toString() +"."+ numxBuilder.toString();
           }
           else
               return builder.toString() +"."+ numxBuilder.toString();
       }else{
           if(nOverToken == 1){
               return "1" + builder.toString();
           }
           else
               return builder.toString();
       }

   }

   public static void main(String[] args){
       String a = "1234.3434343434343434";
       String b = "34343.20000000300000000000";
       System.out.println(add(a, b));
   }
}

</code>