java data structure series

Java/data-structure-with-java/src/main/java/com/javadevjournal/datastructure/tree/rb/RedBlackTree.java

@@ -0,0 +1,170 @@
+package com.javadevjournal.datastructure.tree.rb;
+
+public class RedBlackTree {
+
+    private Node root;
+    private static final boolean RED = false;
+    private static final boolean BLACK = true;
+
+    public boolean insert(int data) {
+        Node n = add(data);
+        if (root == null) {
+            root = n;
+        }
+        fixTree(n);
+        return true;
+    }
+
+    private Node add(int data) {
+        Node x = root;
+        Node y = null;
+        Node n = new Node(data);
+        while (x != null) {
+            y = x;
+            if (x.data > data) {
+                x = x.left;
+            } else {
+                x = x.right;
+            }
+        }
+
+        if (y == null) {
+            y = n;
+        } else if (y.data > data) {
+            n.parent = y;
+            y.left = n;
+        } else {
+            n.parent = y;
+            y.right = n;
+        }
+        return n;
+    }
+
+
+    private void fixTree(Node n) {
+        n.color = RED;
+
+        while (n != null && n != root && n.parent.color == RED) {
+            if (parentOf(n) == leftOf(parentOf(parentOf(n)))) {
+                Node y = rightOf(parentOf(parentOf(n)));
+                if (colorOf(y) == RED) {
+                    // we do color flip.
+                    setColor(parentOf(n), BLACK);
+                    setColor(parentOf(parentOf(n)), RED);
+                    setColor(y, BLACK);
+                    n = parentOf(parentOf(n));
+                } else {
+                    // we do rotate
+                    if (rightOf(parentOf(n)) == n) {
+                        //right child
+                        n = parentOf(n);
+                        leftRotate(parentOf(n));
+
+                    }
+                    setColor(parentOf(n), BLACK);
+                    setColor(parentOf(parentOf(n)), RED);
+                    rightRotate(parentOf(parentOf((n))));
+                }
+            } else {
+
+                Node y = leftOf(parentOf(parentOf(n)));
+                if (colorOf(y) == RED) {
+                    // we do color flip.
+                    setColor(parentOf(n), BLACK);
+                    setColor(parentOf(parentOf(n)), RED);
+                    setColor(y, BLACK);
+                    n = parentOf(parentOf(n));
+                } else {
+                    // we do rotate
+                    if (leftOf(parentOf(n)) == n) {
+                        //right child
+                        n = parentOf(n);
+                        rightRotate(parentOf(n));
+
+                    }
+                    setColor(parentOf(n), BLACK);
+                    setColor(parentOf(parentOf(n)), RED);
+                    leftRotate(parentOf(parentOf((n))));
+                }
+            }
+        }
+
+        root.color = BLACK;
+    }
+
+    private boolean colorOf(Node n) {
+        return n != null ? n.color : BLACK;
+    }
+
+    private Node leftOf(Node n) {
+        return n != null ? n.left : null;
+    }
+
+    private Node rightOf(Node n) {
+        return n != null ? n.right : null;
+    }
+
+    private Node parentOf(Node n) {
+        return n != null ? n.parent : null;
+    }
+
+    private void setColor(Node n, boolean color) {
+        if (n != null) {
+            n.color = color;
+        }
+    }
+
+    private void leftRotate(Node n) {
+        if (n != null) {
+            Node temp = n.right;
+            n.right = temp.left;
+            if (leftOf(temp) != null) {
+                temp.left.parent = n;
+            }
+            temp.parent = n.parent;
+            if (parentOf(n) == null) {
+                root = temp;
+            } else if (leftOf(parentOf(n)) == n) {
+                n.parent.left = temp;
+            } else {
+                n.parent.right = temp;
+            }
+            temp.left = n;
+            n.parent = temp;
+        }
+    }
+
+    private void rightRotate(Node n) {
+        if (n != null) {
+            Node temp = n.left;
+            n.left = temp.right;
+
+            if (rightOf(temp) != null) {
+                temp.right.parent = n;
+            }
+            temp.parent = n.parent;
+            if (parentOf(n) == null) {
+                root = temp;
+            } else if (rightOf(parentOf(n)) == n) {
+                n.parent.right = temp;
+            } else {
+                n.parent.left = temp;
+            }
+            temp.right = n;
+            n.parent = temp;
+
+        }
+    }
+
+
+    public class Node {
+        Node left, right, parent;
+        int data;
+        boolean color;
+
+        public Node(int data) {
+            this.data = data;
+        }
+    }
+
+}

Java/data-structure-with-java/src/main/java/com/javadevjournal/datastructure/tree/rb/RedBlackTreeTest.java

@@ -0,0 +1,15 @@
+package com.javadevjournal.datastructure.tree.rb;
+
+public class RedBlackTreeTest {
+
+    public static void main(String[] args) {
+        RedBlackTree redBlackTree = new RedBlackTree();
+        redBlackTree.insert(15);
+        redBlackTree.insert(6);
+        redBlackTree.insert(5);
+        redBlackTree.insert(25);
+        redBlackTree.insert(27);
+        redBlackTree.insert(7);
+        redBlackTree.insert(19);
+    }
+}