c# B树

news/发布时间2024/6/8 19:44:59

B 树是一种自平衡的树数据结构，通常用于数据库和文件系统等需要大量数据插入、删除和搜索操作的场景。在 C# 中实现 B 树可以帮助实现高效的数据存储和检索功能。下面是一个简单的 B 树的实现示例：

首先，我们需要定义一个节点类 BTreeNode 用于表示 B 树的节点：

class BTreeNode
{public List<int> keys;public int t;  // 最小度数public List<BTreeNode> children;public bool leaf;public BTreeNode(int t, bool leaf){this.t = t;this.leaf = leaf;keys = new List<int>();children = new List<BTreeNode>();}
}

然后，我们创建一个 B 树类 BTree，实现插入、删除和搜索等操作：

class BTree
{private BTreeNode root;private int t;  // 最小度数public BTree(int t){this.t = t;root = new BTreeNode(t, true);}public void Insert(int key){if (root.keys.Count == (2 * t) - 1){BTreeNode newRoot = new BTreeNode(t, false);newRoot.children.Add(root);SplitChild(newRoot, 0);root = newRoot;}InsertNonFull(root, key);}private void InsertNonFull(BTreeNode node, int key){int i = node.keys.Count - 1;if (node.leaf){while (i >= 0 && key < node.keys[i]){i--;}node.keys.Insert(i + 1, key);}else{while (i >= 0 && key < node.keys[i]){i--;}i++;if (node.children[i].keys.Count == (2 * t) - 1){SplitChild(node, i);if (key > node.keys[i]){i++;}}InsertNonFull(node.children[i], key);}}private void SplitChild(BTreeNode parentNode, int childIndex){BTreeNode newChild = parentNode.children[childIndex];BTreeNode newSibling = new BTreeNode(t, newChild.leaf);parentNode.keys.Insert(childIndex, newChild.keys[t - 1]);for (int i = 0; i < t - 1; i++){newSibling.keys.Add(newChild.keys[i + t]);newChild.keys.RemoveAt(t);}if (!newChild.leaf){for (int i = 0; i < t; i++){newSibling.children.Add(newChild.children[i + t]);}for (int i = 0; i < t; i++){newChild.children.RemoveAt(t);}}parentNode.children.Insert(childIndex + 1, newSibling);newChild.keys.RemoveAt(t - 1);}public bool Search(int key){return SearchKey(root, key);}private bool SearchKey(BTreeNode node, int key){int i = 0;while (i < node.keys.Count && key > node.keys[i]){i++;}if (i < node.keys.Count && key == node.keys[i]){return true;}if (node.leaf){return false;}return SearchKey(node.children[i], key);}
}