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| 1 | +#include <stdio.h> |
| 2 | +#include <stdlib.h> |
| 3 | + |
| 4 | +// AVL Tree node structure |
| 5 | +struct Node { |
| 6 | + int data; |
| 7 | + struct Node* left; |
| 8 | + struct Node* right; |
| 9 | + int height; |
| 10 | +}; |
| 11 | + |
| 12 | +// Get the height of a node |
| 13 | +int height(struct Node* node) { |
| 14 | + return (node == NULL) ? 0 : node->height; |
| 15 | +} |
| 16 | + |
| 17 | +// Create a new node |
| 18 | +struct Node* createNode(int data) { |
| 19 | + struct Node* node = (struct Node*)malloc(sizeof(struct Node)); |
| 20 | + node->data = data; |
| 21 | + node->left = node->right = NULL; |
| 22 | + node->height = 1; |
| 23 | + return node; |
| 24 | +} |
| 25 | + |
| 26 | +// Update the height of a node based on its children |
| 27 | +void updateHeight(struct Node* node) { |
| 28 | + node->height = 1 + ((height(node->left) > height(node->right)) ? height(node->left) : height(node->right)); |
| 29 | +} |
| 30 | + |
| 31 | +// Perform a right rotation |
| 32 | +struct Node* rightRotate(struct Node* y) { |
| 33 | + struct Node* x = y->left; |
| 34 | + y->left = x->right; |
| 35 | + x->right = y; |
| 36 | + updateHeight(y); |
| 37 | + updateHeight(x); |
| 38 | + return x; |
| 39 | +} |
| 40 | + |
| 41 | +// Perform a left rotation |
| 42 | +struct Node* leftRotate(struct Node* x) { |
| 43 | + struct Node* y = x->right; |
| 44 | + x->right = y->left; |
| 45 | + y->left = x; |
| 46 | + updateHeight(x); |
| 47 | + updateHeight(y); |
| 48 | + return y; |
| 49 | +} |
| 50 | + |
| 51 | +// Get the balance factor of a node |
| 52 | +int getBalance(struct Node* node) { |
| 53 | + return (node == NULL) ? 0 : height(node->left) - height(node->right); |
| 54 | +} |
| 55 | + |
| 56 | +// Insert a node into the AVL tree |
| 57 | +struct Node* insertNode(struct Node* node, int data) { |
| 58 | + if (node == NULL) return createNode(data); |
| 59 | + |
| 60 | + if (data < node->data) |
| 61 | + node->left = insertNode(node->left, data); |
| 62 | + else if (data > node->data) |
| 63 | + node->right = insertNode(node->right, data); |
| 64 | + else |
| 65 | + return node; |
| 66 | + |
| 67 | + updateHeight(node); |
| 68 | + |
| 69 | + int balance = getBalance(node); |
| 70 | + |
| 71 | + if (balance > 1 && data < node->left->data) |
| 72 | + return rightRotate(node); |
| 73 | + if (balance < -1 && data > node->right->data) |
| 74 | + return leftRotate(node); |
| 75 | + if (balance > 1 && data > node->left->data) { |
| 76 | + node->left = leftRotate(node->left); |
| 77 | + return rightRotate(node); |
| 78 | + } |
| 79 | + if (balance < -1 && data < node->right->data) { |
| 80 | + node->right = rightRotate(node->right); |
| 81 | + return leftRotate(node); |
| 82 | + } |
| 83 | + |
| 84 | + return node; |
| 85 | +} |
| 86 | + |
| 87 | +// Find the node with the minimum value in an AVL tree |
| 88 | +struct Node* findMin(struct Node* node) { |
| 89 | + while (node->left != NULL) node = node->left; |
| 90 | + return node; |
| 91 | +} |
| 92 | + |
| 93 | +// Delete a node from the AVL tree |
| 94 | +struct Node* deleteNode(struct Node* root, int data) { |
| 95 | + if (root == NULL) return NULL; |
| 96 | + |
| 97 | + if (data < root->data) |
| 98 | + root->left = deleteNode(root->left, data); |
| 99 | + else if (data > root->data) |
| 100 | + root->right = deleteNode(root->right, data); |
| 101 | + else { |
| 102 | + if (root->left == NULL || root->right == NULL) { |
| 103 | + struct Node* temp = root->left ? root->left : root->right; |
| 104 | + free(root); |
| 105 | + return temp; |
| 106 | + } |
| 107 | + struct Node* temp = findMin(root->right); |
| 108 | + root->data = temp->data; |
| 109 | + root->right = deleteNode(root->right, temp->data); |
| 110 | + } |
| 111 | + |
| 112 | + updateHeight(root); |
| 113 | + int balance = getBalance(root); |
| 114 | + |
| 115 | + if (balance > 1 && getBalance(root->left) >= 0) |
| 116 | + return rightRotate(root); |
| 117 | + if (balance > 1 && getBalance(root->left) < 0) { |
| 118 | + root->left = leftRotate(root->left); |
| 119 | + return rightRotate(root); |
| 120 | + } |
| 121 | + if (balance < -1 && getBalance(root->right) <= 0) |
| 122 | + return leftRotate(root); |
| 123 | + if (balance < -1 && getBalance(root->right) > 0) { |
| 124 | + root->right = rightRotate(root->right); |
| 125 | + return leftRotate(root); |
| 126 | + } |
| 127 | + |
| 128 | + return root; |
| 129 | +} |
| 130 | + |
| 131 | +// Search for a node in the AVL tree |
| 132 | +int searchNode(struct Node* root, int data) { |
| 133 | + if (root == NULL) return 0; |
| 134 | + if (data == root->data) return 1; |
| 135 | + return (data < root->data) ? searchNode(root->left, data) : searchNode(root->right, data); |
| 136 | +} |
| 137 | + |
| 138 | +// In-order traversal of the AVL tree |
| 139 | +void inorderTraversal(struct Node* root) { |
| 140 | + if (root) { |
| 141 | + inorderTraversal(root->left); |
| 142 | + printf("%d -> ", root->data); |
| 143 | + inorderTraversal(root->right); |
| 144 | + } |
| 145 | +} |
| 146 | + |
| 147 | +int main() { |
| 148 | + struct Node* root = NULL; |
| 149 | + |
| 150 | + root = insertNode(root, 10); |
| 151 | + root = insertNode(root, 20); |
| 152 | + root = insertNode(root, 30); |
| 153 | + root = insertNode(root, 40); |
| 154 | + root = insertNode(root, 50); |
| 155 | + root = insertNode(root, 25); |
| 156 | + |
| 157 | + printf("In-order traversal after insertions:\n"); |
| 158 | + inorderTraversal(root); |
| 159 | + printf("NULL\n"); |
| 160 | + |
| 161 | + // Deletion |
| 162 | + root = deleteNode(root, 20); |
| 163 | + printf("In-order traversal after deleting 20:\n"); |
| 164 | + inorderTraversal(root); |
| 165 | + printf("NULL\n"); |
| 166 | + |
| 167 | + // Searching |
| 168 | + int searchKey = 25; |
| 169 | + printf("Node %d %s in the AVL tree.\n", searchKey, searchNode(root, searchKey) ? "found" : "not found"); |
| 170 | + |
| 171 | + return 0; |
| 172 | +} |
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