小弟刚学JAVA不久,最近弄个快速排序法写了一天还是调试不出来,不知道错在哪,请各位大哥帮忙指点指点。
public class Sort {
int[] a;
public Sort(int[] a){
this.a=a;
}
private void quickSort(int left, int right) {
int i = left;
int j = right;
int t =a[0];
while(true){
while(a[j]>t){
j--;
}
swap(a[i], a[j]);
while(a[i]<t && i<j){
i++;
}
swap(a[i], a[j]);
if(i>=j) break;
}
if(left<i-1)
quickSort(left, i-1);
if(i+1<right)
quickSort(i+1, right);
}
private void swap(int loc1, int loc2) {
int tmp = loc1;
loc1=loc2;
loc2=tmp;
}
public static void main(String[] args){
int[] a ={58,45,61,71,13,53,78};
Sort s = new Sort(a);
s.quickSort(0,6);
for(int i=0;i<7;i++)
System.out.println(a[i]);
}
}
public class Sort {
int[] a;
public Sort(int[] a){
this.a=a;
}
private void quickSort(int left, int right) {
int i = left;
int j = right;
int t =a[0];
while(true){
while(a[j]>t){
j--;
}
swap(a[i], a[j]);
while(a[i]<t && i<j){
i++;
}
swap(a[i], a[j]);
if(i>=j) break;
}
if(left<i-1)
quickSort(left, i-1);
if(i+1<right)
quickSort(i+1, right);
}
private void swap(int loc1, int loc2) {
int tmp = loc1;
loc1=loc2;
loc2=tmp;
}
public static void main(String[] args){
int[] a ={58,45,61,71,13,53,78};
Sort s = new Sort(a);
s.quickSort(0,6);
for(int i=0;i<7;i++)
System.out.println(a[i]);
}
}
// demonstrates quick sort; uses insertion sort for cleanup
// to run this program: C>java QuickSort3App
////////////////////////////////////////////////////////////////
class ArrayIns
{
private long[] theArray; // ref to array theArray
private int nElems; // number of data items
//--------------------------------------------------------------
public ArrayIns(int max) // constructor
{
theArray = new long[max]; // create the array
nElems = 0; // no items yet
}
//--------------------------------------------------------------
public void insert(long value) // put element into array
{
theArray[nElems] = value; // insert it
nElems++; // increment size
}
//--------------------------------------------------------------
public void display() // displays array contents
{
System.out.print("A=");
for(int j=0; j<nElems; j++) // for each element,
System.out.print(theArray[j] + " "); // display it
System.out.println("");
}
//--------------------------------------------------------------
public void quickSort()
{
recQuickSort(0, nElems-1);
// insertionSort(0, nElems-1); // the other option
}
//--------------------------------------------------------------
public void recQuickSort(int left, int right)
{
int size = right-left+1;
if(size < 10) // insertion sort if small
insertionSort(left, right);
else // quicksort if large
{
long median = medianOf3(left, right);
int partition = partitionIt(left, right, median);
recQuickSort(left, partition-1);
recQuickSort(partition+1, right);
}
} // end recQuickSort()
//--------------------------------------------------------------
public long medianOf3(int left, int right)
{
int center = (left+right)/2;
// order left & center
if( theArray[left] > theArray[center] )
swap(left, center);
// order left & right
if( theArray[left] > theArray[right] )
swap(left, right);
// order center & right
if( theArray[center] > theArray[right] )
swap(center, right); swap(center, right-1); // put pivot on right
return theArray[right-1]; // return median value
} // end medianOf3()
//--------------------------------------------------------------
public void swap(int dex1, int dex2) // swap two elements
{
long temp = theArray[dex1]; // A into temp
theArray[dex1] = theArray[dex2]; // B into A
theArray[dex2] = temp; // temp into B
} // end swap(
//--------------------------------------------------------------
public int partitionIt(int left, int right, long pivot)
{
int leftPtr = left; // right of first elem
int rightPtr = right - 1; // left of pivot
while(true)
{
while( theArray[++leftPtr] < pivot ) // find bigger
; // (nop)
while( theArray[--rightPtr] > pivot ) // find smaller
; // (nop)
if(leftPtr >= rightPtr) // if pointers cross,
break; // partition done
else // not crossed, so
swap(leftPtr, rightPtr); // swap elements
} // end while(true)
swap(leftPtr, right-1); // restore pivot
return leftPtr; // return pivot location
} // end partitionIt()
//--------------------------------------------------------------
// insertion sort
public void insertionSort(int left, int right)
{
int in, out;
// sorted on left of out
for(out=left+1; out<=right; out++)
{
long temp = theArray[out]; // remove ed item
in = out; // start shifts at out
// until one is smaller,
while(in>left && theArray[in-1] >= temp)
{
theArray[in] = theArray[in-1]; // shift item to right
--in; // go left one position
}
theArray[in] = temp; // insert ed item
} // end for
} // end insertionSort()
//--------------------------------------------------------------
} // end class ArrayIns
////////////////////////////////////////////////////////////////
class QuickSort3App
{
public static void main(String[] args)
{
int maxSize = 16; // array size
ArrayIns arr; // reference to array
arr = new ArrayIns(maxSize); // create the array for(int j=0; j<maxSize; j++) // fill array with
{ // random numbers
long n = (int)(java.lang.Math.random()*99);
arr.insert(n);
}
arr.display(); // display items
arr.quickSort(); // quicksort them
arr.display(); // display them again
} // end main()
} // end class QuickSort3App
////////////////////////////////////////////////////////////////