Splaytree in C

C/Trees/SplayTree.c

@@ -0,0 +1,138 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct Node {
+    int key;
+    struct Node *left;
+    struct Node *right;
+} Node;
+
+Node *newNode(int key) {
+    Node *node = (Node*) malloc(sizeof(Node));
+    node->key = key;
+    node->left = NULL;
+    node->right = NULL;
+    return node;
+}
+
+Node *rightRotate(Node *x) {
+    Node *y = x->left;
+    x->left = y->right;
+    y->right = x;
+    return y;
+}
+
+Node *leftRotate(Node *x) {
+    Node *y = x->right;
+    x->right = y->left;
+    y->left = x;
+    return y;
+}
+
+Node *splay(Node *root, int key) {
+    if (root == NULL || root->key == key) {
+        return root;
+    }
+
+    if (root->key > key) {
+        if (root->left == NULL) {
+            return root;
+        }
+
+        if (root->left->key > key) {
+            root->left->left = splay(root->left->left, key);
+            root = rightRotate(root);
+        } else if (root->left->key < key) {
+            root->left->right = splay(root->left->right, key);
+            if (root->left->right != NULL) {
+                root->left = leftRotate(root->left);
+            }
+        }
+        return (root->left == NULL) ? root : rightRotate(root);
+    } else {
+        if (root->right == NULL) {
+            return root;
+        }
+
+        if (root->right->key > key) {
+            root->right->left = splay(root->right->left, key);
+            if (root->right->left != NULL) {
+                root->right = rightRotate(root->right);
+            }
+        } else if (root->right->key < key) {
+            root->right->right = splay(root->right->right, key);
+            root = leftRotate(root);
+        }
+
+        return (root->right == NULL) ? root : leftRotate(root);
+    }
+}
+
+Node *search(Node *root, int key) {
+    return splay(root, key);
+}
+
+Node *insert(Node *root, int key) {
+    if (root == NULL) {
+        return newNode(key);
+    }
+
+    root = splay(root, key);
+
+    if (root->key == key) {
+        return root;
+    }
+
+    Node *node = newNode(key);
+
+    if (root->key > key) {
+        node->right = root;
+        node->left = root->left;
+        root->left = NULL;
+    } else {
+        node->left = root;
+        node->right = root->right;
+        root->right = NULL;
+    }
+
+    return node;
+}
+
+
+
+
+Node *deleteNode(Node *root, int key) {
+    if (root == NULL) {
+        return root;
+    }
+
+    root = splay(root, key);
+
+    if (root->key != key) {
+        return root;
+    }
+
+    if (root->left == NULL) {
+        Node *rightChild = root->right;
+        free(root);
+        return rightChild;
+    } else {
+        Node *leftChild = splay(root->left, key);
+        leftChild->right = root->right;
+        free(root);
+        return leftChild;
+    }
+}
+
+int main(void) {
+    Node *root = NULL;
+    root = insert(root, 100);
+    root = insert(root, 50);
+    root = insert(root, 200);
+    root = insert(root, 150);
+    root = insert(root, 250);
+    root = deleteNode(root, 200);
+    root = deleteNode(root, 50);
+
+    return 0;
+}