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9f135d5 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 | // B-tree implementation - self-balancing tree optimized for disk access
// Each node can have multiple keys and children
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define T 3 // Minimum degree (each node has at least T-1 keys)
#define NUM_OPERATIONS 5000
typedef struct BTreeNode {
int *keys;
struct BTreeNode **children;
int num_keys;
int is_leaf;
} BTreeNode;
typedef struct {
BTreeNode *root;
} BTree;
BTreeNode* create_node(int is_leaf) {
BTreeNode *node = (BTreeNode*)malloc(sizeof(BTreeNode));
node->keys = (int*)malloc((2 * T - 1) * sizeof(int));
node->children = (BTreeNode**)malloc(2 * T * sizeof(BTreeNode*));
node->num_keys = 0;
node->is_leaf = is_leaf;
return node;
}
BTree* create_btree() {
BTree *tree = (BTree*)malloc(sizeof(BTree));
tree->root = create_node(1);
return tree;
}
void split_child(BTreeNode *parent, int index) {
BTreeNode *full_child = parent->children[index];
BTreeNode *new_child = create_node(full_child->is_leaf);
new_child->num_keys = T - 1;
// Copy last T-1 keys to new node
for (int i = 0; i < T - 1; i++) {
new_child->keys[i] = full_child->keys[i + T];
}
// Copy last T children if not leaf
if (!full_child->is_leaf) {
for (int i = 0; i < T; i++) {
new_child->children[i] = full_child->children[i + T];
}
}
full_child->num_keys = T - 1;
// Shift parent's children
for (int i = parent->num_keys; i > index; i--) {
parent->children[i + 1] = parent->children[i];
}
parent->children[index + 1] = new_child;
// Shift parent's keys
for (int i = parent->num_keys - 1; i >= index; i--) {
parent->keys[i + 1] = parent->keys[i];
}
parent->keys[index] = full_child->keys[T - 1];
parent->num_keys++;
}
void insert_non_full(BTreeNode *node, int key) {
int i = node->num_keys - 1;
if (node->is_leaf) {
// Shift keys and insert
while (i >= 0 && key < node->keys[i]) {
node->keys[i + 1] = node->keys[i];
i--;
}
node->keys[i + 1] = key;
node->num_keys++;
} else {
// Find child to insert into
while (i >= 0 && key < node->keys[i]) {
i--;
}
i++;
if (node->children[i]->num_keys == 2 * T - 1) {
split_child(node, i);
if (key > node->keys[i]) {
i++;
}
}
insert_non_full(node->children[i], key);
}
}
void btree_insert(BTree *tree, int key) {
BTreeNode *root = tree->root;
if (root->num_keys == 2 * T - 1) {
BTreeNode *new_root = create_node(0);
new_root->children[0] = root;
split_child(new_root, 0);
tree->root = new_root;
insert_non_full(new_root, key);
} else {
insert_non_full(root, key);
}
}
BTreeNode* search(BTreeNode *node, int key) {
int i = 0;
while (i < node->num_keys && key > node->keys[i]) {
i++;
}
if (i < node->num_keys && key == node->keys[i]) {
return node;
}
if (node->is_leaf) {
return NULL;
}
return search(node->children[i], key);
}
int get_height(BTreeNode *node) {
if (!node || node->is_leaf) return 1;
return 1 + get_height(node->children[0]);
}
void free_btree(BTreeNode *node) {
if (!node) return;
if (!node->is_leaf) {
for (int i = 0; i <= node->num_keys; i++) {
free_btree(node->children[i]);
}
}
free(node->keys);
free(node->children);
free(node);
}
int main() {
BTree *tree = create_btree();
unsigned int seed = 42;
clock_t start = clock();
// Insert operations
for (int i = 0; i < NUM_OPERATIONS; i++) {
seed = seed * 1103515245 + 12345;
int key = seed % 50000;
btree_insert(tree, key);
}
// Search operations
int found = 0;
for (int i = 0; i < NUM_OPERATIONS / 2; i++) {
seed = seed * 1103515245 + 12345;
int key = seed % 50000;
if (search(tree->root, key)) {
found++;
}
}
int height = get_height(tree->root);
clock_t end = clock();
double time_spent = (double)(end - start) / CLOCKS_PER_SEC;
printf("B-tree (degree=%d): %d operations, %.6f seconds\n", T, NUM_OPERATIONS, time_spent);
printf("Tree height: %d, Found: %d\n", height, found);
free_btree(tree->root);
free(tree);
return 0;
}
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