Merge remote-tracking branch 'central/master'

.gitignore

@@ -41,3 +41,5 @@ SpringDataInjectionDemo/.mvn/wrapper/maven-wrapper.properties
 spring-call-getters-using-reflection/.mvn/wrapper/maven-wrapper.properties
 
 spring-check-if-a-property-is-null/.mvn/wrapper/maven-wrapper.properties
+*.springBeans
+

README.md

@@ -23,4 +23,4 @@ Any IDE can be used to work with the projects, but if you're using Eclipse, cons
 
 CI - Jenkins
 ================================
-This tutorials project is being built **[>> HERE](https://rest-security.ci.cloudbees.com/job/tutorials/)**
+This tutorials project is being built **[>> HERE](https://rest-security.ci.cloudbees.com/job/github%20projects%20Jobs/job/tutorials/)**

algorithms/README.md

@@ -8,3 +8,4 @@
 - [Check If a Number Is Prime in Java](http://www.baeldung.com/java-prime-numbers)
 - [Example of Hill Climbing Algorithm](http://www.baeldung.com/java-hill-climbing-algorithm)
 - [Monte Carlo Tree Search for Tic-Tac-Toe Game](http://www.baeldung.com/java-monte-carlo-tree-search)
+- [String Search Algorithms for Large Texts](http://www.baeldung.com/java-full-text-search-algorithms)

algorithms/src/main/java/com/baeldung/algorithms/binarysearch/BinarySearch.java

@@ -0,0 +1,55 @@
+package com.baeldung.algorithms.binarysearch;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class BinarySearch {
+
+    public int runBinarySearchIteratively(int[] sortedArray, int key, int low, int high) {
+
+        int index = Integer.MAX_VALUE;
+
+        while (low <= high) {
+
+            int mid = (low + high) / 2;
+
+            if (sortedArray[mid] < key) {
+                low = mid + 1;
+            } else if (sortedArray[mid] > key) {
+                high = mid - 1;
+            } else if (sortedArray[mid] == key) {
+                index = mid;
+                break;
+            }
+        }
+        return index;
+    }
+
+    public int runBinarySearchRecursively(int[] sortedArray, int key, int low, int high) {
+
+        int middle = (low + high) / 2;
+        if (high < low) {
+            return -1;
+        }
+
+        if (key == sortedArray[middle]) {
+          return middle;
+        } else if (key < sortedArray[middle]) {
+          return runBinarySearchRecursively(sortedArray, key, low, middle - 1);
+        } else {
+          return runBinarySearchRecursively(sortedArray, key, middle + 1, high);
+        }
+    }
+
+    public int runBinarySearchUsingJavaArrays(int[] sortedArray, Integer key) {
+        int index = Arrays.binarySearch(sortedArray, key);
+        return index;
+    }
+
+    public int runBinarySearchUsingJavaCollections(List<Integer> sortedList, Integer key) {
+        int index = Collections.binarySearch(sortedList, key);
+        return index;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionBruteForce.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleDetectionBruteForce {
+
+    public static <T> CycleDetectionResult<T> detectCycle(Node<T> head) {
+        if (head == null) {
+            return new CycleDetectionResult<>(false, null);
+        }
+
+        Node<T> it1 = head;
+        int nodesTraversedByOuter = 0;
+        while (it1 != null && it1.next != null) {
+            it1 = it1.next;
+            nodesTraversedByOuter++;
+
+            int x = nodesTraversedByOuter;
+            Node<T> it2 = head;
+            int noOfTimesCurrentNodeVisited = 0;
+
+            while (x > 0) {
+                it2 = it2.next;
+
+                if (it2 == it1) {
+                    noOfTimesCurrentNodeVisited++;
+                }
+
+                if (noOfTimesCurrentNodeVisited == 2) {
+                    return new CycleDetectionResult<>(true, it1);
+                }
+
+                x--;
+            }
+        }
+
+        return new CycleDetectionResult<>(false, null);
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionByFastAndSlowIterators.java

@@ -0,0 +1,25 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleDetectionByFastAndSlowIterators {
+
+    public static <T> CycleDetectionResult<T> detectCycle(Node<T> head) {
+        if (head == null) {
+            return new CycleDetectionResult<>(false, null);
+        }
+
+        Node<T> slow = head;
+        Node<T> fast = head;
+
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+
+            if (slow == fast) {
+                return new CycleDetectionResult<>(true, fast);
+            }
+        }
+
+        return new CycleDetectionResult<>(false, null);
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionByHashing.java

@@ -0,0 +1,27 @@
+package com.baeldung.algorithms.linkedlist;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class CycleDetectionByHashing {
+
+    public static <T> CycleDetectionResult<T> detectCycle(Node<T> head) {
+        if (head == null) {
+            return new CycleDetectionResult<>(false, null);
+        }
+
+        Set<Node<T>> set = new HashSet<>();
+        Node<T> node = head;
+
+        while (node != null) {
+            if (set.contains(node)) {
+                return new CycleDetectionResult<>(true, node);
+            }
+            set.add(node);
+            node = node.next;
+        }
+
+        return new CycleDetectionResult<>(false, null);
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/CycleDetectionResult.java

@@ -0,0 +1,12 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleDetectionResult<T> {
+    boolean cycleExists;
+    Node<T> node;
+
+    public CycleDetectionResult(boolean cycleExists, Node<T> node) {
+        super();
+        this.cycleExists = cycleExists;
+        this.node = node;
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/CycleRemovalBruteForce.java

@@ -0,0 +1,56 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleRemovalBruteForce {
+
+    public static <T> boolean detectAndRemoveCycle(Node<T> head) {
+        CycleDetectionResult<T> result = CycleDetectionByFastAndSlowIterators.detectCycle(head);
+
+        if (result.cycleExists) {
+            removeCycle(result.node, head);
+        }
+
+        return result.cycleExists;
+    }
+
+    /**
+     * @param loopNodeParam - reference to the node where Flyods cycle 
+     * finding algorithm ends, i.e. the fast and the slow iterators
+     * meet.
+     * @param head - reference to the head of the list
+     */
+    private static <T> void removeCycle(Node<T> loopNodeParam, Node<T> head) {
+        Node<T> it = head;
+
+        while (it != null) {
+            if (isNodeReachableFromLoopNode(it, loopNodeParam)) {
+                Node<T> loopStart = it;
+                findEndNodeAndBreakCycle(loopStart);
+                break;
+            }
+            it = it.next;
+        }
+    }
+
+    private static <T> boolean isNodeReachableFromLoopNode(Node<T> it, Node<T> loopNodeParam) {
+        Node<T> loopNode = loopNodeParam;
+
+        do {
+            if (it == loopNode) {
+                return true;
+            }
+            loopNode = loopNode.next;
+        } while (loopNode.next != loopNodeParam);
+
+        return false;
+    }
+
+    private static <T> void findEndNodeAndBreakCycle(Node<T> loopStartParam) {
+        Node<T> loopStart = loopStartParam;
+
+        while (loopStart.next != loopStartParam) {
+            loopStart = loopStart.next;
+        }
+
+        loopStart.next = null;
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/CycleRemovalByCountingLoopNodes.java

@@ -0,0 +1,44 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleRemovalByCountingLoopNodes {
+
+    public static <T> boolean detectAndRemoveCycle(Node<T> head) {
+        CycleDetectionResult<T> result = CycleDetectionByFastAndSlowIterators.detectCycle(head);
+
+        if (result.cycleExists) {
+            removeCycle(result.node, head);
+        }
+
+        return result.cycleExists;
+    }
+
+    private static <T> void removeCycle(Node<T> loopNodeParam, Node<T> head) {
+        int cycleLength = calculateCycleLength(loopNodeParam);
+        Node<T> cycleLengthAdvancedIterator = head;
+        Node<T> it = head;
+
+        for (int i = 0; i < cycleLength; i++) {
+            cycleLengthAdvancedIterator = cycleLengthAdvancedIterator.next;
+        }
+
+        while (it.next != cycleLengthAdvancedIterator.next) {
+            it = it.next;
+            cycleLengthAdvancedIterator = cycleLengthAdvancedIterator.next;
+        }
+
+        cycleLengthAdvancedIterator.next = null;
+    }
+
+    private static <T> int calculateCycleLength(Node<T> loopNodeParam) {
+        Node<T> loopNode = loopNodeParam;
+        int length = 1;
+
+        while (loopNode.next != loopNodeParam) {
+            length++;
+            loopNode = loopNode.next;
+        }
+
+        return length;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/CycleRemovalWithoutCountingLoopNodes.java

@@ -0,0 +1,27 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class CycleRemovalWithoutCountingLoopNodes {
+
+    public static <T> boolean detectAndRemoveCycle(Node<T> head) {
+        CycleDetectionResult<T> result = CycleDetectionByFastAndSlowIterators.detectCycle(head);
+
+        if (result.cycleExists) {
+            removeCycle(result.node, head);
+        }
+
+        return result.cycleExists;
+    }
+
+    private static <T> void removeCycle(Node<T> meetingPointParam, Node<T> head) {
+        Node<T> loopNode = meetingPointParam;
+        Node<T> it = head;
+
+        while (loopNode.next != it.next) {
+            it = it.next;
+            loopNode = loopNode.next;
+        }
+
+        loopNode.next = null;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/linkedlist/Node.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.linkedlist;
+
+public class Node<T> {
+    T data;
+    Node<T> next;
+
+    public static <T> Node<T> createNewNode(T data, Node<T> next) {
+        Node<T> node = new Node<T>();
+        node.data = data;
+        node.next = next;
+        return node;
+    }
+
+    public static <T> void traverseList(Node<T> root) {
+        if (root == null) {
+            return;
+        }
+
+        Node<T> node = root;
+        while (node != null) {
+            System.out.println(node.data);
+            node = node.next;
+        }
+    }
+
+    public static <T> Node<T> getTail(Node<T> root) {
+        if (root == null) {
+            return null;
+        }
+
+        Node<T> node = root;
+        while (node.next != null) {
+            node = node.next;
+        }
+        return node;
+    }
+
+}