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Simple AVL Tree Insert
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#include <stdio.h> | |
#include <stdlib.h> | |
typedef struct node { | |
int value; | |
int height; | |
struct node *left; | |
struct node *right; | |
} Node; | |
typedef struct { | |
struct node *root; | |
} Tree; | |
int maxHeight(Node *a, Node *b) { | |
int weightA = (a == NULL)? 0 : a->height; | |
int weightB = (b == NULL)? 0 : b->height; | |
return (weightA > weightB)? weightA : weightB; | |
} | |
int determineBalance(Node *node) { | |
if (node != NULL) { | |
int leftWeight = (node->left == NULL)? 0 : node->left->height; | |
int rightWeight = (node->right == NULL)? 0 : node->right->height; | |
return leftWeight - rightWeight; | |
} | |
return 0; | |
} | |
Node *newNode(int value) { | |
Node *node = (Node *)malloc(sizeof(Node *)); | |
node->value = value; | |
node->height = 1; | |
node->left = NULL; | |
node->right = NULL; | |
return node; | |
} | |
Node *rotateRight(Node *node) { | |
Node *oldLeft = node->left; | |
Node *temp = oldLeft->right; | |
oldLeft->right = node; | |
node->left = temp; | |
node->height = maxHeight(node->left, node->right) + 1; | |
oldLeft->height = maxHeight(oldLeft->left, oldLeft->right) + 1; | |
return oldLeft; | |
} | |
Node *rotateLeft(Node *node) { | |
Node *oldRight = node->right; | |
Node *temp = oldRight->left; | |
oldRight->left = node; | |
node->right = temp; | |
node->height = maxHeight(node->left, node->right) + 1; | |
oldRight->height = maxHeight(oldRight->left, oldRight->right) + 1; | |
return oldRight; | |
} | |
Node *insert(Node *node, int value) { | |
int balance; | |
if (node == NULL) { | |
return newNode(value); | |
} | |
if (value < node->value) { | |
node->left = insert(node->left, value); | |
} else if (value > node->value) { | |
node->right = insert(node->right, value); | |
} else { | |
return node; | |
} | |
// TREE BALANCING PART // | |
node->height = 1 + maxHeight(node->left, node->right); | |
balance = determineBalance(node); | |
if ((balance > 1) && (value < node->left->value)) { | |
return rotateRight(node); | |
} | |
if ((balance < -1) && (value > node->right->value)) { | |
return rotateLeft(node); | |
} | |
if ((balance > 1) && (value > node->left->value)) { | |
node->left = rotateLeft(node->left); | |
return rotateRight(node); | |
} | |
if ((balance < -1) && (value < node->right->value)) { | |
node->right = rotateRight(node->right); | |
return rotateLeft(node); | |
} | |
return node; | |
} | |
void printNode(Node *node) { | |
if (node != NULL) { | |
printf("%d", node->value); | |
if (node->left != NULL || node->right != NULL) { | |
printf("("); | |
printNode(node->left); | |
if (node->left != NULL && node->right) { | |
printf(","); | |
} | |
printNode(node->right); | |
printf(")"); | |
} | |
} | |
} | |
Tree *newTree() { | |
Tree *tree = (Tree *)malloc(sizeof(Tree *)); | |
tree->root = NULL; | |
return tree; | |
} | |
void insertToTree(Tree *tree, int value) { | |
tree->root = insert(tree->root, value); | |
} | |
void printTree(Tree *tree) { | |
printNode(tree->root); | |
printf("\n"); | |
} | |
int main() { | |
Tree *tree = newTree(); | |
insertToTree(tree, 1); | |
insertToTree(tree, 2); | |
insertToTree(tree, 3); | |
insertToTree(tree, 4); | |
insertToTree(tree, 5); | |
insertToTree(tree, 6); | |
insertToTree(tree, 7); | |
printTree(tree); // -> 4(2(1,3),6(5,7)) | |
return 0; | |
} |
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gcc -o avl-tree.bin avl-tree.c && ./avl-tree.bin |
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