Question

我仍然遇到一个越界错误，我不知道为什么。我添加了一个print语句来查看firstList和secondList实际上是什么，并且它都搞砸了我将在下面发布输出，所以也许有人可以看到出了什么问题。

输出：

Names before sorting: [Justin, Butch, Mandy, Sarah, Jack, Natalie, Brent, Ashley]
[Justin, null, null, null]
[Justin, Butch, null, null]
[Justin, Butch, Mandy, null]
[Justin, Butch, Mandy, Sarah]
[Natalie, null, null, null]
[Natalie, Natalie, null, null]
[Natalie, Natalie, Natalie, null]
[Natalie, Natalie, Natalie, Natalie]
[Justin, null]
[Justin, Butch]
[Sarah, null]
[Sarah, Sarah]
[Justin]
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2
    at MergeSorter.sort(MergeSorter.java:22)
    at MergeSorter.sort(MergeSorter.java:25)
    at MergeSorter.sort(MergeSorter.java:25)
    at MergeSorter.main(MergeSorter.java:68)

正如你所看到的，阵列都搞砸了，我不知道为什么，请帮忙！

import java.util.*;

public class MergeSorter
{
   public static void sort(String[] names)
   {
      if (names.length <= 1)
      {
         return;
      }
      String[] firstList = new String[names.length / 2];
      String[] secondList = new String[names.length - firstList.length];

      for (int i = 0; i < firstList.length; i++)
      {
         firstList[i] = names[i];
         System.out.println(Arrays.toString(firstList));

      } 
      for (int i = 0; i < secondList.length; i++)
      {  
         secondList[i] = names[firstList.length + 1];
         System.out.println(Arrays.toString(secondList));
      }
      sort(firstList);
      sort(secondList);
      merge(firstList, secondList, names);
   }   

   private static void merge(String[] firstList, String[] secondList, String[] names)
   {
      int first = 0;
      int second = 0;
      int names1 = 0;

      while (first < firstList.length && second < secondList.length)
      {
         if (firstList[first].compareTo(secondList[second]) < 0)
         {
            names[names1] = firstList[first];
            first++;
         }
         else
         {
          names[names1] = secondList[second];
          second++;
         }
         names1++;
      }
      while(first < firstList.length)
      {
         names[names1] = firstList[first];
         first++;
         names1++;
      }
      while(second < secondList.length)
      {
         names[names1] = secondList[second];
         second++;
         names1++;
      }
   }
   public static void main(String[] args)
   {

      String[] names = {"Justin", "Butch", "Mandy", "Sarah", "Jack", "Natalie", "Brent", "Ashley"};
      System.out.println("Names before sorting: " + Arrays.toString(names));
      sort(names);
      System.out.println("Names after sorting: " + Arrays.toString(names));
   }   
}

Answer 1

您的错误在第26行：

secondList[i] = names[firstList.length + 1];

这显然超出了数组的范围，将其更改为：

secondList[i] = names[firstList.length + i];

看看你是否得到了理想的结果：

Names before sorting: [Justin, Butch, Mandy, Sarah, Jack, Natalie, Brent, Ashley]
[Justin, null, null, null]
[Justin, Butch, null, null]
[Justin, Butch, Mandy, null]
[Justin, Butch, Mandy, Sarah]
[Jack, null, null, null]
[Jack, Natalie, null, null]
[Jack, Natalie, Brent, null]
[Jack, Natalie, Brent, Ashley]
[Justin, null]
[Justin, Butch]
[Mandy, null]
[Mandy, Sarah]
[Justin]
[Butch]
[Mandy]
[Sarah]
[Jack, null]
[Jack, Natalie]
[Brent, null]
[Brent, Ashley]
[Jack]
[Natalie]
[Brent]
[Ashley]
Names after sorting: [Ashley, Brent, Butch, Jack, Justin, Mandy, Natalie, Sarah]

Answer 2

You can use this code  as well to compare the string  as it is simple to compare string :

Collections.sort(list, new Comparator<String>() {
        @Override
        public int compare(String s1, String s2) {
            return s1.compareToIgnoreCase(s2);
        }
    });

遇到阵列问题

2 个答案: