add linear search

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 260 insertions, 0 deletions

diff --git a/src/algorithms/searching/LinearSearch.java b/src/algorithms/searching/LinearSearch.java
new file mode 100644
index 0000000..0e621b7
--- /dev/null
+++ b/src/algorithms/searching/LinearSearch.java
@@ -0,0 +1,260 @@
+/**
+ * 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
+}
+