Java 堆排序的不正确实现
这是从网站上获取的修改后的实现Java 堆排序的不正确实现,java,debugging,sorting,heapsort,Java,Debugging,Sorting,Heapsort,这是从网站上获取的修改后的实现 import java.io.File; import java.io.FileNotFoundException; import java.util.*; public class HeapSort { static int heapsize; public static void main(String args[]) { Vector<Integer> container = new Vector&
import java.io.File;
import java.io.FileNotFoundException;
import java.util.*;
public class HeapSort
{
static int heapsize;
public static void main(String args[])
{
Vector<Integer> container = new Vector<Integer>(); // container used to store txt file integers
Scanner myScanner = new Scanner("foo"); // variable used to read file
String userinput="data1.txt";
try
{
//open filename
//got problem , must think how to do relative path instead of absolute path
File inputfile = new File("C:\\Users\\8382c\\workspace\\AdvanceAlgorithmA3_Heapsort\\src\\" + userinput);
myScanner = new Scanner(inputfile);
}
catch(FileNotFoundException e)
{
System.out.println("File cant be found");
}
String line = myScanner.nextLine(); //read 1st line which contains the number of numbers to be sorted
while (myScanner.hasNext())
{
container.add(myScanner.nextInt());
}
heapsize = container.size();
System.out.println(heapsize);
sort(container);
int x =10;
/*for (int i=0 ; i < container.size() ; i ++)
{
System.out.println(container.get(i));
}*/
//http://www.sanfoundry.com/java-program-implement-heap-sort/
}
public static void swap(Vector<Integer> container, int i, int j)
{
/*int tmp = arr[i];
arr[i] = arr[j];
arr[j] = tmp;*/
int tmp = container.get(i);
container.set(i, container.get(j));
container.set(j, tmp);
}
public static void maxheap(Vector<Integer> container, int i) //ensure max number is the parent
{
int left = 2*i ;
int right = 2*i + 1;
int max = i;
if (left <= heapsize && container.get(left) > container.get(i));
max = left;
if (right <= heapsize && container.get(right) > container.get(max))
max = right;
if (max != i)
{
swap(container, i, max);
maxheap(container, max);
}
}
public static void heapify(Vector<Integer> container) //built a heap
{
heapsize = container.size()-1;
for (int i = heapsize/2; i >= 0; i--)
maxheap(container, i);
}
public static void sort(Vector<Integer> container)
{
heapify(container);
for (int i = heapsize; i > 0; i--)
{
swap(container,0, i);
heapsize = heapsize-1;
maxheap(container, 0);
}
}
}
我的调试器不起作用,因为每次我跨过函数max heap时,我都会得到尚未解决的问题
我不明白数组越界错误是从哪里产生的,我在过去的两个小时里查看了实现代码,没有发现任何错误,有人能告诉我我的代码有什么问题吗???这行末尾有一个分号:
if (left <= heapsize && container.get(left) > container.get(i));
这意味着下一行总是在运行,而不仅仅是在条件为真时。去掉分号,你就可以走了
if (left <= heapsize && container.get(left) > container.get(i));