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authorMattias Andrée <maandree@operamail.com>2014-01-21 07:17:18 +0100
committerMattias Andrée <maandree@operamail.com>2014-01-21 07:17:18 +0100
commit901ad3ca98d42c12fe84d5ccfe2c897fc639498b (patch)
treea6affb8808556bbbfeddbf238bc33640993d28a7
parentbit reversing (diff)
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add linear search
Signed-off-by: Mattias Andrée <maandree@operamail.com>
-rw-r--r--src/algorithms/searching/LinearSearch.java260
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
+}
+