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/**
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package algorithms.searching;
import java.util.*;
/**
* Linear search class. Linear search runs in linear time, constant memory,
* and imposes no requirements on the list. Linear is not recommended for
* sorted lists.
*/
public class LinearSearch
{
/**
* The value returned if the item was not found
*/
public static final int NOT_FOUND = -1;
/**
* Finds the index of the first occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @return The index of the first occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfFirstEqual(Object item, Object[] array)
{
return indexOfFirstEqual(item, array, 0, -1);
}
/**
* Finds the index of the first occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start Offset for the list or search range
* @return The index of the first occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfFirstEqual(Object item, Object[] array, int start)
{
return indexOfFirstEqual(item, array, start, -1);
}
/**
* Finds the index of the first occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start Offset for the list or search range
* @param end End of the list or search range
* @return The index of the first occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfFirstEqual(Object item, Object[] array, int start, int end)
{
int i = start < 0 ? (array.length - start) : start;
int n = end < 0 ? (array.length - end) : end;
for (;;)
{
if (i == n)
break;
if ((array[i] == null) == (item == null))
{
if (item == null)
return i;
if (array[i].equals(item))
return i;
}
i++;
}
return NOT_FOUND;
}
/**
* Finds the index of the last occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @return The index of the last occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfLastEqual(Object item, Object[] array)
{
return indexOfLastEqual(item, array, -1, 0);
}
/**
* Finds the index of the last occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start End offset for the list or search range
* @return The index of the last occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfLastEqual(Object item, Object[] array, int start)
{
return indexOfLastEqual(item, array, start, 0);
}
/**
* Finds the index of the last occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start End offset for the list or search range
* @param end Beginning offset for the list or search range
* @return The index of the last occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfLastEqual(Object item, Object[] array, int start, int end)
{
int i = start < 0 ? (array.length - start) : start;
int n = end < 0 ? (array.length - end) : end;
for (;;)
{
if (i == n)
break;
if ((array[i] == null) == (item == null))
{
if (item == null)
return i;
if (array[i].equals(item))
return i;
}
i--;
}
return NOT_FOUND;
}
£>for T in boolean char byte short int long float double Object; do
/**
* Finds the index of the first occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @return The index of the first occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfFirst(£{T} item, £{T}[] array)
{
return indexOfFirst(item, array, 0, -1);
}
/**
* Finds the index of the first occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start Offset for the list or search range
* @return The index of the first occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfFirst(£{T} item, £{T}[] array, int start)
{
return indexOfFirst(item, array, start, -1);
}
/**
* Finds the index of the first occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start Offset for the list or search range
* @param end End of the list or search range
* @return The index of the first occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfFirst(£{T} item, £{T}[] array, int start, int end)
{
int i = start < 0 ? (array.length - start) : start;
int n = end < 0 ? (array.length - end) : end;
for (;;)
{
if (i == n)
break;
if (array[i] == item)
return i;
i++;
}
return NOT_FOUND;
}
/**
* Finds the index of the last occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @return The index of the last occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfLast(£{T} item, £{T}[] array)
{
return indexOfLast(item, array, -1, 0);
}
/**
* Finds the index of the last occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start End offset for the list or search range
* @return The index of the last occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfLast(£{T} item, £{T}[] array, int start)
{
return indexOfLast(item, array, start, 0);
}
/**
* Finds the index of the last occurance of an item in a list
*
* @param item The item for which to search
* @param array The list in which to search
* @param start End offset for the list or search range
* @param end Beginning offset for the list or search range
* @return The index of the last occurance of the item within the list, {@link #NOT_FOUND} if it was not found
*/
public static int indexOfLast(£{T} item, £{T}[] array, int start, int end)
{
int i = start < 0 ? (array.length - start) : start;
int n = end < 0 ? (array.length - end) : end;
for (;;)
{
if (i == n)
break;
if (array[i] == item)
return i;
i--;
}
return NOT_FOUND;
}
£>done
}
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