排序程序中的Java错误
我收到一个我无法追踪或解决的错误。
/**
* Problem 23.13
* ExcutionTimeForSorting class obtains the execution time
* of selection sort, bubble sort, merge sort, quick sort, heap sort,
* and radiz sort for input size 5,000, 10,000, 15,000, 20,000,
* 25,000, and 30,000.
*/
import java.util.ArrayList;
import java.util.*;
public class ExecutionTimeForSorting
{
//start of main method
public static void main (String [] args)
{
//creating a two-dimensional array for selection sort
int [] [] selectionArray = new int [6] [];
selectionArray[0] = new int [50000];
selectionArray[1] = new int [100000];
selectionArray[2] = new int [150000];
selectionArray[3] = new int [200000];
selectionArray[4] = new int [250000];
selectionArray[5] = new int [300000];
//creating a two-dimensional array for bubble sort
int [] [] bubbleArray = new int [6] [];
bubbleArray[0] = new int [50000];
bubbleArray[1] = new int [100000];
bubbleArray[2] = new int [150000];
bubbleArray[3] = new int [200000];
bubbleArray[4] = new int [250000];
bubbleArray[5] = new int [300000];
//creating a two-dimensional array for merge sort
int [] [] mergeArray = new int [6] [];
mergeArray[0] = new int [50000];
mergeArray[1] = new int [100000];
mergeArray[2] = new int [150000];
mergeArray[3] = new int [200000];
mergeArray[4] = new int [250000];
mergeArray[5] = new int [300000];
//creating a two-dimensional array for quick sort
int [] [] quickArray = new int [6] [];
quickArray[0] = new int [50000];
quickArray[1] = new int [100000];
quickArray[2] = new int [150000];
quickArray[3] = new int [200000];
quickArray[4] = new int [250000];
quickArray[5] = new int [300000];
//creating a two-dimensional array for heap sort
int [] [] heapArray = new int [6] [];
heapArray[0] = new int [50000];
heapArray[1] = new int [100000];
heapArray[2] = new int [150000];
heapArray[3] = new int [200000];
heapArray[4] = new int [250000];
heapArray[5] = new int [300000];
//creating a two-dimensional array for radix sort
int [] [] radixArray = new int [6] [];
radixArray[0] = new int [50000];
radixArray[1] = new int [100000];
radixArray[2] = new int [150000];
radixArray[3] = new int [200000];
radixArray[4] = new int [250000];
radixArray[5] = new int [300000];
//declaring two variables to find elapsed time
long startTime = 0, endTime = 0;
//creating one-dimensional array to store elapsed times
long [] selectionExecutionTime = new long [6];
long [] bubbleExecutionTime = new long [6];
long [] mergeExecutionTime = new long [6];
long [] quickExecutionTime = new long [6];
long [] heapExecutionTime = new long [6];
long [] radixExecutionTime = new long [6];
//storing the same integers randomly in all two-dimensional arrays
for (int i = 0; i < selectionArray.length; i++)
{
for (int j = 0; j < selectionArray[i].length; j++)
{
int number = (int) (Math.random() * 1000);
selectionArray[i][j] = number;
bubbleArray[i][j] = number;
mergeArray[i][j] = number;
quickArray[i][j] = number;
heapArray[i][j] = number;
radixArray[i][j] = number;
}
}
//finding the elapsed time for selection sort
for (int i = 0; i < selectionArray.length; i++)
{
startTime = System.currentTimeMillis();
//call to selectionSort method
SelectionSort.selectionSort(selectionArray[i]);
endTime = System.currentTimeMillis();
selectionExecutionTime[i] = endTime - startTime;
startTime = 0;
endTime = 0;
}
//finding the elapsed time for bubble sort
for (int i = 0; i < bubbleArray.length; i++)
{
startTime = System.currentTimeMillis();
//call to BubbleSort method
BubbleSort.bubbleSort(selectionArray[i]);
endTime = System.currentTimeMillis();
bubbleExecutionTime[i] = endTime - startTime;
startTime = 0;
endTime = 0;
}
//finding the elapsed time for merge sort
for (int i = 0; i < mergeArray.length; i++)
{
startTime = System.currentTimeMillis();
//call to mergeSort method
MergeSort.mergeSort(selectionArray[i]);
endTime = System.currentTimeMillis();
mergeExecutionTime[i] = endTime - startTime;
startTime = 0;
endTime = 0;
}
//finding the elapsed time for quick sort
for (int i = 0; i < quickArray.length; i++)
{
startTime = System.currentTimeMillis();
//call to quickSort method
QuickSortNonRecursive.quickSort(selectionArray[i]);
endTime = System.currentTimeMillis();
quickExecutionTime[i] = endTime - startTime;
startTime = 0;
endTime = 0;
}
//finding the elapsed time for heap sort
for (int i = 0; i < heapArray.length; i++)
{
startTime = System.currentTimeMillis();
//call to heapSort method
HeapSort.heapSort(selectionArray[i]);
endTime = System.currentTimeMillis();
heapExecutionTime[i] = endTime - startTime;
startTime = 0;
endTime = 0;
}
//finding the elapsed time for radix sort
for (int i = 0; i < radixArray.length; i++)
{
startTime = System.currentTimeMillis();
//call to radixSort method
RadixSort.radixSort(selectionArray[i]);
endTime = System.currentTimeMillis();
radixExecutionTime[i] = endTime - startTime;
startTime = 0;
endTime = 0;
}
/*displaying all elapsed times of all sorting techniques
in a table format */
System.out.printf("%10s%2s%15s%13s%13s%13s%13s%13\n",
"Array size", "|", "Selection Sort", "Bubble Sort",
"Merge Sort", "Quick Sort", "Heap Sort", "Radix Sort");
System.out.println("-----------|-----------------" +
"-------------------------------------------" +
"---------------------");
for (int i = 0; i < selectionArray.length; i++)
{
System.out.printf("%7s%5s%13s%14s%13s%13s%13s%13s\n",
selectionArray[i].length, "|",
selectionExecutionTime[i],
bubbleExecutionTime[i],
mergeExecutionTime[i],
quickExecutionTime[i],
heapExecutionTime[i],
radixExecutionTime[i]);
}
}//end of main method
}//end of ExecutionTimeForSorting class
//SelectionSort Class demonstrates selectionSort method
class SelectionSort
{
//the method for sorting the numbers
public static void selectionSort (int[] list)
{
for (int i = 0; i < list.length -1; i++)
{
//finding the minimum in the list
int currentMin = list[i];
int currentMinIndex = i;
for (int j = i + 1; j < list.length; j++)
{
if (currentMin > list[j])
{
currentMin = list[j];
currentMinIndex = j;
}
}
//swapping list[i] with list [currentMinIndex] if necessary
if (currentMinIndex != i)
{
list[currentMinIndex] = list[i];
list[i] = currentMin;
}
}
}//end of selectionSort method
}//end of SelectionSort class
//BubbleSort class demonstrates the method bubbleSort
class BubbleSort
{
//bubble sort method
public static void bubbleSort(int[] list)
{
boolean needNextPass = true;
for (int k = 1; k < list.length && needNextPass; k++)
{
//array may be sorted and next pass not needed
needNextPass = false;
for (int i = 0; i < list.length - k; i++)
{
if (list[i] > list [i + 1])
{
//swap list[i] with list [i+1]
int temp = list[i];
list[i] = list[i + 1];
list[i + 1] = temp;
//Next pass still needed
needNextPass = true;
}
}
}
}//end of bubbleSort method
}//end of BubbleSort class
//MergeSort class demonstrates the methods mergeSort and merge
class MergeSort
{
//the method for sorting the numbers
public static void mergeSort (int[] list)
{
if (list.length > 1)
{
//merge sort the first half
int[] firstHalf = new int[list.length/2];
System.arraycopy(list, 0, firstHalf, 0, list.length/2);
mergeSort(firstHalf);
//merge sort the second half
int secondHalfLength = list.length - list.length/2;
int[] secondHalf = new int[secondHalfLength];
System.arraycopy(list, list.length/2, secondHalf, 0, secondHalfLength);
mergeSort(secondHalf);
//merge first half with second half into list
merge (firstHalf, secondHalf, list);
}
}//end of mergeSort method
//merge two sorted lists
public static void merge (int[] list1, int[] list2, int[] temp)
{
int current1 = 0;//current index in list1
int current2 = 0;//current index in list2
int current3 = 0;//current index in temp
while(current1 < list1.length && current2 < list2.length)
{
if (list1[current1] < list2[current2])
temp[current3++] = list1[current1++];
else
temp[current3++] = list2[current2++];
}
while (current1 < list1.length)
temp [current3++] = list1[current1++];
while (current2 < list2.length)
temp[current3++] = list2[current2++];
}//end of merge method
}//end of MergeSort class
/*QuickSortNonRecursice class demonstrates the mehods quickSort,
quickSort helper and partition*/
class QuickSortNonRecursive
{
//quickSort method
public static void quickSort(int[] list)
{
quickSort(list, 0, list.length - 1);
}//end of quickSort method
//quickSort helper method
public static void quickSort (int[] list, int first, int last)
{
//creating a stack of integers
Stack<Integer> stack = new Stack<Integer>();
stack.push(first);
stack.push(last);
while(!stack.empty())
{
last = (Integer)stack.pop();
first = (Integer)stack.pop();
if(last <= first)
continue;
//get the pivot point
int pivotIndex = partition(last, first, last);
if((pivotIndex - first) > (last - pivotIndex))
{
stack.push(first);
stack.push(pivotIndex - 1);
}
stack.push(pivotIndex + 1);
stack.push(last);
if ((last - pivotIndex) >= (pivotIndex - first))
{
stack.push(first);
stack.push(pivotIndex - 1);
}
}
}//end of quickSort helper method
//partition the array list[first...last]
private static int partition(int[] list, int first, int last)
{
//choose the first element as the pivot
int pivot = list[first];
int low = first +1;//index for forward search
int high = last;//index for backward search
while (high > low)
{
//search forward from left
while (low <= high && list[low] <= pivot)
low++;
//search backward from right
while( low <= high && list[high] > pivot)
high--;
//swap two elements in the list
if (high > low)
{
int temp = list[high];
list[high] = list[low];
list[low] = temp;
}
}
while(high > first && list[high] >= pivot)
high--;
//swap pivot with list[high]
if (pivot > list[high])
{
list[first] = list[high];
list[high] = pivot;
}
else
{
return first;
}
}//end of partition method
}//end of QuickSortNonRecursive class
//HeapSort class demonstrates the method heapSort
class HeapSort
{
//heap sort method
public static <E extends Comparable> void heapSort (E[] list)
{
//creating a heap of integers
Heap<E> heap = new Heap<E>();
//adding elements to the heap
for (int i = 0; i < list.length; i++)
heap.add(list[i]);
//remove elements from the heap
for (int i = list.length - 1; i >= 0; i--)
list[i] = heap.remove();
}//end of heapSort method
}//end of HeapSort class
/*RadixSort class demonsrates the methods radixSort, radixSort
helper, and getPosition*/
class RadixSort
{
//radixSort method
public static void radixSort (int[] list)
{
radixSort(list,5);
}//end of radixSort method
//radixSort helper method
public static void radixSort (int[] list, int mostDigits)
{
ArrayList<Integer>[] radix = new ArrayList[10];
for (int i = 0; i < radix.length; i++)
{
radix[i] = new ArrayList<Integer>();
}
for (int index = 0; index < list.length; index++)
{
for (int i = 0; i < radix.length; i++)
{
radix[i].clear();
}
for (int i = 0; i < list.length; i++)
{
int position = getPosition(list[i],
index);
radix[position].add(list[i]);
}
int k = 0; //index of list
for (int i = 0; i < radix.length; i++)
{
for (int j = 0; j< radix[i].size(); j++)
list[k++] = radix[i].get(j);
}
}
}//end of radixSort helper method
//getPosition method
public static int getPosition(int value, int index)
{
int result = 1;
for (int i = 0; i < index; i++)
result = result * 10;
return (value / result) % 10;
}//end of getPosition method
}//end of RadixSort class
我得到的错误附后......
1：
1 个答案:
答案 0 :(得分：2)
第一个错误： 我可能是错的，但看起来你的heapSort方法只适用于实现Comparable接口的项，这意味着你需要使用Integer类而不是int基本类型。 https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html
第二个错误： 你过去了＃34;最后＆＃34;作为分区（）的第一个参数，而不是＆＃34; list＆＃34;。
第三个错误： 您尝试声明Heap类型的对象，但您从未定义过Heap类。我不知道Java中有任何名为Heap的本地类。
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