我的代码在哈希搜索方法的第二个while循环中陷入困境。似乎条件保持不变，如果密钥不在数据集中或者如果找到密钥，它们最终应该变为假。有人可以帮我找到这个错误吗？
由于
////// 这就是整体..我一直在努力......仍然无法找到错误。
public void HashedSearch()
{
HSAverageAccessTime = 0;
HSAverageCompSuc = 0;
HSAverageCompFailed = 0;
HSNumberKeysSuc = 0;
HSNumberKeysFailed = 0;
Initialize();
int SearchKey;
int TotalNumberOfComparisons;
int address;
int M;
M = FindPrime();
for(int i=0; i<NumberOfDataItems; i++)
{
address = OriginalArray[i] % M;
if (HashedArray[address]== -1)
HashedArray[address]= OriginalArray[i];
else
{
address = (address+1) % M;
while(HashedArray[address]!=-1)
{
address=(address+1)%M;
}
HashedArray[address]=OriginalArray[i];
}
}
System.out.println("after mapping" + M);
long startTime = System.nanoTime();
boolean found = false;
for (int k = 0; k <NumberOfKeys; k++)
{
found = false;
SearchKey = KeysArray[k];
TotalNumberOfComparisons = 0;
address = KeysArray[k] % M;
//System.out.println("address" + address);
//System.out.println(" inside if 1 --- address" + address);
while ( HashedArray[address]!= SearchKey && HashedArray[address]!= -1)
{
if (HashedArray [address] == SearchKey)
{
found = true;
TotalNumberOfComparisons++;
HSAverageCompSuc = HSAverageCompSuc + TotalNumberOfComparisons;
BSNumberKeysSuc ++;
}
else
{
System.out.println("Stuck after here");
HSAverageCompFailed = HSAverageCompFailed + TotalNumberOfComparisons;
HSNumberKeysFailed ++;
//address=(address+1)%M;
address++;
}
System.out.println(" outside while --- found" + found);
//if(HashedArray[address] == SearchKey)
//found = true;
//else found = false;
//address=(address+1)%M;
//address++;
}
if(found)
{
HSAverageCompSuc = HSAverageCompSuc + TotalNumberOfComparisons;
BSNumberKeysSuc ++;
}
else
{
HSAverageCompFailed = HSAverageCompFailed + TotalNumberOfComparisons;
HSNumberKeysFailed ++;
}
}
long estimatedTime = System.nanoTime() - startTime;
if (NumberOfKeys != 0)
HSAverageAccessTime = Math.round((estimatedTime/NumberOfKeys));
else
HSAverageAccessTime = 0;
if(HSNumberKeysSuc != 0)
HSAverageCompSuc = Math.round (HSAverageCompSuc / HSNumberKeysSuc) ;
else
HSAverageCompSuc = 0;
if (HSNumberKeysFailed != 0)
HSAverageCompFailed = Math.round (HSAverageCompFailed / HSNumberKeysFailed) ;
else
HSNumberKeysFailed = 0;
System.out.println("time after search" + estimatedTime);
return;
}
答案 0 :(得分：0)
while ( HashedArray[address]!= SearchKey && HashedArray[address]!= -1)
{
address=(address+1)%M;
}
如果 SearchKey 或 -1 不在 HashedArray 中，您的循环永远不会终止。除非您发布完整的代码，否则我不能再给您任何澄清。
答案 1 :(得分：0)
@Bashir @KevinDiTraglia @Steinar
import javax.swing.*;
//File-related imports
import java.io.IOException;
import java.util.Scanner;
import java.io.File;
import java.util.Arrays;
import java.math.*;
public class ArrayOperations
{
// File Parameters
String DataFilePath;
String DataFileName;
String KeysFilePath;
String KeysFileName;
int NumberOfDataItems;
int NumberOfKeys ;
int N ;
int BucketHashArraySize;
int NoBuckets;
//Array
int[] OriginalArray = new int[1000000];
int[] SortedArray = new int[1000000];
int[] HashedArray = new int[2000000];
int[] BucketHashedArray = new int[2000000];
int[] KeysArray = new int[1000000];
long SSAverageAccessTime;
long SSAverageCompSuc ;
long SSAverageCompFailed;
long SSNumberKeysSuc ;
long SSNumberKeysFailed ;
long BSAverageAccessTime;
long BSAverageCompSuc ;
long BSAverageCompFailed;
long BSNumberKeysSuc ;
long BSNumberKeysFailed ;
long HSAverageAccessTime;
long HSAverageCompSuc ;
long HSAverageCompFailed;
long HSNumberKeysSuc ;
long HSNumberKeysFailed ;
public ArrayOperations()
{
// File Parameters
DataFilePath = null;
DataFileName = null;
KeysFilePath = null;
KeysFileName = null;
NumberOfDataItems=0;
NumberOfKeys =0;
N =0;
BucketHashArraySize = 0;
NoBuckets =0;
// Statistics
SSAverageAccessTime = 0;
SSAverageCompSuc = 0;
SSAverageCompFailed = 0;
SSNumberKeysSuc = 0;
SSNumberKeysFailed = 0;
BSAverageAccessTime = 0;
BSAverageCompSuc = 0;
BSAverageCompFailed = 0;
BSNumberKeysSuc = 0;
BSNumberKeysFailed = 0;
HSAverageAccessTime = 0;
HSAverageCompSuc = 0;
HSAverageCompFailed = 0;
HSNumberKeysSuc = 0;
HSNumberKeysFailed = 0;
}
public void ReadDataFile() throws IOException
{
JFileChooser chooser = new JFileChooser();
chooser.setDialogType(JFileChooser.OPEN_DIALOG );
chooser.setDialogTitle("Open Data File");
int returnVal = chooser.showOpenDialog(null);
if( returnVal == JFileChooser.APPROVE_OPTION)
{
DataFilePath = chooser.getSelectedFile().getPath();
DataFileName = chooser.getSelectedFile().getName();
}
// read data file and copy it to original array
if (DataFilePath != null)
{
try
{
int index = 0;
Scanner integerTextFile = new Scanner(new File(DataFilePath));
while (integerTextFile.hasNext())
{
// read the next integer
OriginalArray[index] = integerTextFile.nextInt();
index++;
}
// end of file detected
integerTextFile.close();
NumberOfDataItems = index;
}
catch (IOException ioe)
{
System.exit(0);
}
}
else
NumberOfDataItems = 0;
}
public void ReadKeysFile() throws IOException
{
JFileChooser chooser = new JFileChooser();
chooser.setDialogType(JFileChooser.OPEN_DIALOG );
chooser.setDialogTitle("Open Keys File");
int returnVal = chooser.showOpenDialog(null);
if( returnVal == JFileChooser.APPROVE_OPTION)
{
KeysFilePath = chooser.getSelectedFile().getPath();
KeysFileName = chooser.getSelectedFile().getName();
}
// read data file and copy it to original array
if (KeysFilePath != null)
{
try
{
int index = 0;
Scanner integerTextFile = new Scanner(new File(KeysFilePath));
while (integerTextFile.hasNext())
{
// read the next integer
KeysArray[index]= integerTextFile.nextInt();
index++;
}
// end of file detected
integerTextFile.close();
NumberOfKeys = index;
}
catch (IOException ioe)
{
System.exit(0);
}
}
else
NumberOfKeys = 0;
}
public void SequentialSearch()
{
SSAverageAccessTime = 0;
SSAverageCompSuc = 0;
SSAverageCompFailed = 0;
SSNumberKeysSuc = 0;
SSNumberKeysFailed = 0;
int SearchKey;
int TotalNumberOfComparisons;
long startTime = System.nanoTime();
boolean found = false;
for (int k=0; k<NumberOfKeys; k++)
{
found = false;
SearchKey = KeysArray[k];
TotalNumberOfComparisons = 0;
for (int d=0; d<NumberOfDataItems; d++)
{
TotalNumberOfComparisons++;
if (SearchKey == OriginalArray[d])
{
found = true;
}
if (found)break;
}
if(found)
{
SSAverageCompSuc = SSAverageCompSuc + TotalNumberOfComparisons;
SSNumberKeysSuc ++;
}
else
{
SSAverageCompFailed = SSAverageCompFailed + TotalNumberOfComparisons;
SSNumberKeysFailed ++;
}
}
long estimatedTime = System.nanoTime() - startTime;
if (NumberOfKeys != 0)
SSAverageAccessTime = Math.round((estimatedTime/NumberOfKeys));
else
SSAverageAccessTime = 0;
if(SSNumberKeysSuc != 0)
SSAverageCompSuc = Math.round (SSAverageCompSuc / SSNumberKeysSuc) ;
else
SSAverageCompSuc = 0;
if (SSNumberKeysFailed != 0)
SSAverageCompFailed = Math.round (SSAverageCompFailed / SSNumberKeysFailed) ;
else
SSNumberKeysFailed = 0;
return;
}
public void BinarySearch()
{
BSAverageAccessTime = 0 ;
BSAverageCompSuc = 0 ;
BSAverageCompFailed = 0 ;
BSNumberKeysSuc = 0 ;
BSNumberKeysFailed = 0 ;
int SearchKey;
int TotalNumberOfComparisons;
boolean found = false;
for (int i=0; i<NumberOfDataItems; i++)
{
SortedArray[i] = OriginalArray[i];
}
Arrays.sort(SortedArray);
long startTime = System.nanoTime();
for (int k=0; k<NumberOfKeys; k++)
{
found = false;
SearchKey = KeysArray[k];
TotalNumberOfComparisons = 0;
//binary starts
int start = 0;
int end = SortedArray.length - 1;
int middle;
while ( end >= start )
{
middle = ( start + end )/ 2; // element in middle of array
if ( SortedArray[middle] == SearchKey )
{
TotalNumberOfComparisons++;
found = true;
}
else
if ( SortedArray[middle] > SearchKey )
{ TotalNumberOfComparisons++;
end = middle - 1;
} // search left side of array
else
{ TotalNumberOfComparisons++;
start = middle + 1; } // search right side of array
if (found)
break;
//binaryends
}
if(found)
{
BSAverageCompSuc = BSAverageCompSuc + TotalNumberOfComparisons;
BSNumberKeysSuc ++;
}
else
{
BSAverageCompFailed = BSAverageCompFailed + TotalNumberOfComparisons;
BSNumberKeysFailed ++;
}
}
long estimatedTime = System.nanoTime() - startTime;
if (NumberOfKeys != 0)
BSAverageAccessTime = Math.round((estimatedTime/NumberOfKeys));
else
BSAverageAccessTime = 0;
if(BSNumberKeysSuc != 0)
BSAverageCompSuc = Math.round (BSAverageCompSuc / BSNumberKeysSuc) ;
else
BSAverageCompSuc = 0;
if (BSNumberKeysFailed != 0)
BSAverageCompFailed = Math.round (BSAverageCompFailed / BSNumberKeysFailed) ;
else
BSNumberKeysFailed = 0;
return;
}
public void HashedSearch()
{
HSAverageAccessTime = 0;
HSAverageCompSuc = 0;
HSAverageCompFailed = 0;
HSNumberKeysSuc = 0;
HSNumberKeysFailed = 0;
Initialize();
int SearchKey;
int TotalNumberOfComparisons;
int address;
int M;
M = FindPrime();
for(int i=0; i<NumberOfDataItems; i++)
{
address = OriginalArray[i] % M;
if (HashedArray[address]== -1)
HashedArray[address]= OriginalArray[i];
else
{
address = (address+1) % M;
while(HashedArray[address]!=-1)
{
address=(address+1)%M;
}
HashedArray[address]=OriginalArray[i];
}
}
System.out.println("after mapping" + M);
long startTime = System.nanoTime();
boolean found = false;
for (int k = 0; k <NumberOfKeys; k++)
{
found = false;
SearchKey = KeysArray[k];
TotalNumberOfComparisons = 0;
address = KeysArray[k] % M;
//System.out.println("address" + address);
//System.out.println(" inside if 1 --- address" + address);
while ( HashedArray[address]!= SearchKey && HashedArray[address]!= -1)
{
if (HashedArray [address] == SearchKey)
{
found = true;
TotalNumberOfComparisons++;
HSAverageCompSuc = HSAverageCompSuc + TotalNumberOfComparisons;
BSNumberKeysSuc ++;
}
else
{
System.out.println("Stuck after here");
HSAverageCompFailed = HSAverageCompFailed + TotalNumberOfComparisons;
HSNumberKeysFailed ++;
//address=(address+1)%M;
address++;
}
System.out.println(" outside while --- found" + found);
//if(HashedArray[address] == SearchKey)
//found = true;
//else found = false;
//address=(address+1)%M;
//address++;
}
if(found)
{
HSAverageCompSuc = HSAverageCompSuc + TotalNumberOfComparisons;
BSNumberKeysSuc ++;
}
else
{
HSAverageCompFailed = HSAverageCompFailed + TotalNumberOfComparisons;
HSNumberKeysFailed ++;
}
}
long estimatedTime = System.nanoTime() - startTime;
if (NumberOfKeys != 0)
HSAverageAccessTime = Math.round((estimatedTime/NumberOfKeys));
else
HSAverageAccessTime = 0;
if(HSNumberKeysSuc != 0)
HSAverageCompSuc = Math.round (HSAverageCompSuc / HSNumberKeysSuc) ;
else
HSAverageCompSuc = 0;
if (HSNumberKeysFailed != 0)
HSAverageCompFailed = Math.round (HSAverageCompFailed / HSNumberKeysFailed) ;
else
HSNumberKeysFailed = 0;
System.out.println("time after search" + estimatedTime);
return;
}
public int FindPrime()
{
boolean prime = true;
for(int i=NumberOfDataItems * 2-1; i>=0; i--)
{
System.out.println(" i = " +i);
prime = true;
for(int J =2; J< Math.sqrt(i); J++)
{
if (i % J == 0)
{
prime = false;
}
if (prime == false) break;
}
if (prime == true)
{
System.out.println(i);
return i;
}
}
return -1;
}
public void Initialize()
{
for (int i=0; i<NumberOfDataItems; i++)
{
HashedArray[i] = -1;
}
}
public void BHSearch()
{
}
}