{"id":199645,"date":"2025-05-06T08:44:10","date_gmt":"2025-05-06T00:44:10","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199645\/"},"modified":"2025-05-06T08:44:10","modified_gmt":"2025-05-06T00:44:10","slug":"python%e5%ae%9e%e7%8e%b0%e8%af%a6%e7%bb%86%e7%9a%84b%e6%a0%91%e5%8e%9f%e7%90%86%e5%92%8c%e4%bb%a3%e7%a0%81%e8%a7%a3%e6%9e%90","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199645\/","title":{"rendered":"Python\u5b9e\u73b0\u8be6\u7ec6\u7684B+\u6811\u539f\u7406\u548c\u4ee3\u7801\u89e3\u6790"},"content":{"rendered":"

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Python\u5b9e\u73b0\u8be6\u7ec6\u7684B+\u6811\u539f\u7406\u548c\u4ee3\u7801\u89e3\u6790<\/h1>\n

\u4e0d\u77e5\u9053\u5927\u5bb6\u662f\u5426\u719f\u6089\uff1f\u4eca\u5929\u6211\u5c06\u7ed9\u5927\u5bb6\u4ecb\u7ecd\uff0c\u8fd9\u7bc7\u6587\u7ae0\u4e3b\u8981\u4f1a\u8bb2\u5230\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u4f60\u5728\u770b\u5b8c\u672c\u7bc7\u6587\u7ae0\u540e\uff0c\u6709\u66f4\u597d\u7684\u5efa\u8bae\u6216\u8005\u53d1\u73b0\u54ea\u91cc\u6709\u95ee\u9898\uff0c\u5e0c\u671b\u5927\u5bb6\u90fd\u80fd\u79ef\u6781\u8bc4\u8bba\u6307\u51fa\uff0c\u8c22\u8c22\uff01\u5e0c\u671b\u6211\u4eec\u80fd\u4e00\u8d77\u52a0\u6cb9\u8fdb\u6b65\uff01<\/p>\n

B+\u6811\u662f\u81ea\u5e73\u8861\u6811\u7684\u9ad8\u7ea7\u5f62\u5f0f\uff0c\u5176\u4e2d\u6240\u6709\u503c\u90fd\u5b58\u5728\u4e8e\u53f6\u7ea7\u4e2d\u3002B+\u6811\u6240\u6709\u53f6\u5b50\u90fd\u5904\u4e8e\u540c\u4e00\u6c34\u5e73\uff0c\u6bcf\u4e2a\u8282\u70b9\u7684\u5b50\u8282\u70b9\u6570\u91cf\u22652\u3002B+\u6811\u4e0eB\u6811\u7684\u533a\u522b\u662f\u5404\u8282\u70b9\u5728B\u6811\u4e0a\u4e0d\u662f\u76f8\u4e92\u8fde\u63a5\uff0c\u800c\u5728B+\u6811\u4e0a\u662f\u76f8\u4e92\u8fde\u63a5\u7684\u3002<\/p>\n

B+\u6811\u591a\u7ea7\u7d22\u5f15\u7ed3\u6784\u56fe<\/h3>\n

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B+\u6811\u641c\u7d22\u89c4\u5219<\/h3>\n

1\u3001\u4ece\u6839\u8282\u70b9\u5f00\u59cb\u3002\u5c06k\u4e0e\u6839\u8282\u70b9\u7684\u952e\u8fdb\u884c\u6bd4\u8f83[k1,k2,k3,……k(m-1)]<\/p>\n

2\u3001\u5982\u679ck<k1\uff0c\u5230\u6839\u8282\u70b9\u7684\u5de6\u5b50\u8282\u70b9\uff1b<\/p>\n

3\u3001\u5982\u679ck==k1\uff0c\u518d\u548c\u01372\u6bd4\u8f83.\uff0c\u5982\u679ck<k2,k\u4ecb\u4e8e\u01371\u548c\u01372\u4e4b\u95f4\uff0c\u5728\u5de6\u5b50\u8282\u70b9\u4e2d\u641c\u7d22\u01372<\/p>\n

4\u3001\u5982\u679ck>k2\uff0c\u7ee7\u7eed\u548ck3,k4,…k(m-1)\u6bd4\u8f83\uff0c\u91cd\u590d\u5982\u7b2c2\u6b65\u548c\u7b2c3\u6b65<\/p>\n

5\u3001\u76f4\u5230\u8282\u70b9\u4e2d\u5b58\u5728k\uff0c\u5219\u8fd4\u56detrue\uff0c\u5426\u5219\u8fd4\u56defalse\u3002<\/p>\n

Python\u5b9e\u73b0B+\u6811<\/h3>\n
import math\r\nclass Node:\r\n    def __init__(self, order):\r\n        self.order = order\r\n        self.values = []\r\n        self.keys = []\r\n        self.nextKey = None\r\n        self.parent = None\r\n        self.check_leaf = False\r\n\r\n    def insert_at_leaf(self, leaf, value, key):\r\n        if (self.values):\r\n            temp1 = self.values\r\n            for i in range(len(temp1)):\r\n                if (value == temp1[i]):\r\n                    self.keys[i].append(key)\r\n                    break\r\n                elif (value < temp1[i]):\r\n                    self.values = self.values[:i] + [value] + self.values[i:]\r\n                    self.keys = self.keys[:i] + [[key]] + self.keys[i:]\r\n                    break\r\n                elif (i + 1 == len(temp1)):\r\n                    self.values.append(value)\r\n                    self.keys.append([key])\r\n                    break\r\n        else:\r\n            self.values = [value]\r\n            self.keys = [[key]]\r\n\r\nclass BplusTree:\r\n    def __init__(self, order):\r\n        self.root = Node(order)\r\n        self.root.check_leaf = True\r\n\r\n    def insert(self, value, key):\r\n        value = str(value)\r\n        old_node = self.search(value)\r\n        old_node.insert_at_leaf(old_node, value, key)\r\n\r\n        if (len(old_node.values) == old_node.order):\r\n            node1 = Node(old_node.order)\r\n            node1.check_leaf = True\r\n            node1.parent = old_node.parent\r\n            mid = int(math.ceil(old_node.order \/ 2)) - 1\r\n            node1.values = old_node.values[mid + 1:]\r\n            node1.keys = old_node.keys[mid + 1:]\r\n            node1.nextKey = old_node.nextKey\r\n            old_node.values = old_node.values[:mid + 1]\r\n            old_node.keys = old_node.keys[:mid + 1]\r\n            old_node.nextKey = node1\r\n            self.insert_in_parent(old_node, node1.values[0], node1)\r\n\r\n    def search(self, value):\r\n        current_node = self.root\r\n        while(current_node.check_leaf == False):\r\n            temp2 = current_node.values\r\n            for i in range(len(temp2)):\r\n                if (value == temp2[i]):\r\n                    current_node = current_node.keys[i + 1]\r\n                    break\r\n                elif (value < temp2[i]):\r\n                    current_node = current_node.keys[i]\r\n                    break\r\n                elif (i + 1 == len(current_node.values)):\r\n                    current_node = current_node.keys[i + 1]\r\n                    break\r\n        return current_node\r\n\r\n    def find(self, value, key):\r\n        l = self.search(value)\r\n        for i, item in enumerate(l.values):\r\n            if item == value:\r\n                if key in l.keys[i]:\r\n                    return True\r\n                else:\r\n                    return False\r\n        return False\r\n\r\n    def insert_in_parent(self, n, value, ndash):\r\n        if (self.root == n):\r\n            rootNode = Node(n.order)\r\n            rootNode.values = [value]\r\n            rootNode.keys = [n, ndash]\r\n            self.root = rootNode\r\n            n.parent = rootNode\r\n            ndash.parent = rootNode\r\n            return\r\n\r\n        parentNode = n.parent\r\n        temp3 = parentNode.keys\r\n        for i in range(len(temp3)):\r\n            if (temp3[i] == n):\r\n                parentNode.values = parentNode.values[:i] + \\\r\n                    [value] + parentNode.values[i:]\r\n                parentNode.keys = parentNode.keys[:i +\r\n                                                  1] + [ndash] + parentNode.keys[i + 1:]\r\n                if (len(parentNode.keys) > parentNode.order):\r\n                    parentdash = Node(parentNode.order)\r\n                    parentdash.parent = parentNode.parent\r\n                    mid = int(math.ceil(parentNode.order \/ 2)) - 1\r\n                    parentdash.values = parentNode.values[mid + 1:]\r\n                    parentdash.keys = parentNode.keys[mid + 1:]\r\n                    value_ = parentNode.values[mid]\r\n                    if (mid == 0):\r\n                        parentNode.values = parentNode.values[:mid + 1]\r\n                    else:\r\n                        parentNode.values = parentNode.values[:mid]\r\n                    parentNode.keys = parentNode.keys[:mid + 1]\r\n                    for j in parentNode.keys:\r\n                        j.parent = parentNode\r\n                    for j in parentdash.keys:\r\n                        j.parent = parentdash\r\n                    self.insert_in_parent(parentNode, value_, parentdash)\r\n\r\n    def delete(self, value, key):\r\n        node_ = self.search(value)\r\n\r\n        temp = 0\r\n        for i, item in enumerate(node_.values):\r\n            if item == value:\r\n                temp = 1\r\n\r\n                if key in node_.keys[i]:\r\n                    if len(node_.keys[i]) > 1:\r\n                        node_.keys[i].pop(node_.keys[i].index(key))\r\n                    elif node_ == self.root:\r\n                        node_.values.pop(i)\r\n                        node_.keys.pop(i)\r\n                    else:\r\n                        node_.keys[i].pop(node_.keys[i].index(key))\r\n                        del node_.keys[i]\r\n                        node_.values.pop(node_.values.index(value))\r\n                        self.deleteEntry(node_, value, key)\r\n                else:\r\n                    print(\"Value not in Key\")\r\n                    return\r\n        if temp == 0:\r\n            print(\"Value not in Tree\")\r\n            return\r\n\r\n    def deleteEntry(self, node_, value, key):\r\n\r\n        if not node_.check_leaf:\r\n            for i, item in enumerate(node_.keys):\r\n                if item == key:\r\n                    node_.keys.pop(i)\r\n                    break\r\n            for i, item in enumerate(node_.values):\r\n                if item == value:\r\n                    node_.values.pop(i)\r\n                    break\r\n\r\n        if self.root == node_ and len(node_.keys) == 1:\r\n            self.root = node_.keys[0]\r\n            node_.keys[0].parent = None\r\n            del node_\r\n            return\r\n        elif (len(node_.keys) < int(math.ceil(node_.order \/ 2)) and node_.check_leaf == False) or (len(node_.values) < int(math.ceil((node_.order - 1) \/ 2)) and node_.check_leaf == True):\r\n\r\n            is_predecessor = 0\r\n            parentNode = node_.parent\r\n            PrevNode = -1\r\n            NextNode = -1\r\n            PrevK = -1\r\n            PostK = -1\r\n            for i, item in enumerate(parentNode.keys):\r\n\r\n                if item == node_:\r\n                    if i > 0:\r\n                        PrevNode = parentNode.keys[i - 1]\r\n                        PrevK = parentNode.values[i - 1]\r\n\r\n                    if i < len(parentNode.keys) - 1:\r\n                        NextNode = parentNode.keys[i + 1]\r\n                        PostK = parentNode.values[i]\r\n\r\n            if PrevNode == -1:\r\n                ndash = NextNode\r\n                value_ = PostK\r\n            elif NextNode == -1:\r\n                is_predecessor = 1\r\n                ndash = PrevNode\r\n                value_ = PrevK\r\n            else:\r\n                if len(node_.values) + len(NextNode.values) < node_.order:\r\n                    ndash = NextNode\r\n                    value_ = PostK\r\n                else:\r\n                    is_predecessor = 1\r\n                    ndash = PrevNode\r\n                    value_ = PrevK\r\n\r\n            if len(node_.values) + len(ndash.values) < node_.order:\r\n                if is_predecessor == 0:\r\n                    node_, ndash = ndash, node_\r\n                ndash.keys += node_.keys\r\n                if not node_.check_leaf:\r\n                    ndash.values.append(value_)\r\n                else:\r\n                    ndash.nextKey = node_.nextKey\r\n                ndash.values += node_.values\r\n\r\n                if not ndash.check_leaf:\r\n                    for j in ndash.keys:\r\n                        j.parent = ndash\r\n\r\n                self.deleteEntry(node_.parent, value_, node_)\r\n                del node_\r\n            else:\r\n                if is_predecessor == 1:\r\n                    if not node_.check_leaf:\r\n                        ndashpm = ndash.keys.pop(-1)\r\n                        ndashkm_1 = ndash.values.pop(-1)\r\n                        node_.keys = [ndashpm] + node_.keys\r\n                        node_.values = [value_] + node_.values\r\n                        parentNode = node_.parent\r\n                        for i, item in enumerate(parentNode.values):\r\n                            if item == value_:\r\n                                p.values[i] = ndashkm_1\r\n                                break\r\n                    else:\r\n                        ndashpm = ndash.keys.pop(-1)\r\n                        ndashkm = ndash.values.pop(-1)\r\n                        node_.keys = [ndashpm] + node_.keys\r\n                        node_.values = [ndashkm] + node_.values\r\n                        parentNode = node_.parent\r\n                        for i, item in enumerate(p.values):\r\n                            if item == value_:\r\n                                parentNode.values[i] = ndashkm\r\n                                break\r\n                else:\r\n                    if not node_.check_leaf:\r\n                        ndashp0 = ndash.keys.pop(0)\r\n                        ndashk0 = ndash.values.pop(0)\r\n                        node_.keys = node_.keys + [ndashp0]\r\n                        node_.values = node_.values + [value_]\r\n                        parentNode = node_.parent\r\n                        for i, item in enumerate(parentNode.values):\r\n                            if item == value_:\r\n                                parentNode.values[i] = ndashk0\r\n                                break\r\n                    else:\r\n                        ndashp0 = ndash.keys.pop(0)\r\n                        ndashk0 = ndash.values.pop(0)\r\n                        node_.keys = node_.keys + [ndashp0]\r\n                        node_.values = node_.values + [ndashk0]\r\n                        parentNode = node_.parent\r\n                        for i, item in enumerate(parentNode.values):\r\n                            if item == value_:\r\n                                parentNode.values[i] = ndash.values[0]\r\n                                break\r\n\r\n                if not ndash.check_leaf:\r\n                    for j in ndash.keys:\r\n                        j.parent = ndash\r\n                if not node_.check_leaf:\r\n                    for j in node_.keys:\r\n                        j.parent = node_\r\n                if not parentNode.check_leaf:\r\n                    for j in parentNode.keys:\r\n                        j.parent = parentNode\r\n\r\ndef printTree(tree):\r\n    lst = [tree.root]\r\n    level = [0]\r\n    leaf = None\r\n    flag = 0\r\n    lev_leaf = 0\r\n\r\n    node1 = Node(str(level[0]) + str(tree.root.values))\r\n\r\n    while (len(lst) != 0):\r\n        x = lst.pop(0)\r\n        lev = level.pop(0)\r\n        if (x.check_leaf == False):\r\n            for i, item in enumerate(x.keys):\r\n                print(item.values)\r\n        else:\r\n            for i, item in enumerate(x.keys):\r\n                print(item.values)\r\n            if (flag == 0):\r\n                lev_leaf = lev\r\n                leaf = x\r\n                flag = 1\r\n\r\n\r\nrecord_len = 3\r\nbplustree = BplusTree(record_len)\r\nbplustree.insert('5', '33')\r\nbplustree.insert('15', '21')\r\nbplustree.insert('25', '31')\r\nbplustree.insert('35', '41')\r\nbplustree.insert('45', '10')\r\n\r\nprintTree(bplustree)\r\n\r\nif(bplustree.find('5', '34')):\r\n    print(\"Found\")\r\nelse:\r\n    print(\"Not found\")<\/pre>\n
\u597d\u4e86\uff0c\u672c\u6587\u5230\u6b64\u7ed3\u675f\uff0c\u5e26\u5927\u5bb6\u4e86\u89e3\u4e86\u300aPython\u5b9e\u73b0\u8be6\u7ec6\u7684B+\u6811\u539f\u7406\u548c\u4ee3\u7801\u89e3\u6790\u300b\uff0c\u5e0c\u671b\u672c\u6587\u5bf9\u4f60\u6709\u6240\u5e2e\u52a9\uff01\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff0c\u7ed9\u5927\u5bb6\u5206\u4eab\u66f4\u591a\u6570\u636e\u5e93\u77e5\u8bc6\uff01<\/p>\n
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\n
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Python\u5b9e\u73b0\u8be6\u7ec6\u7684B+\u6811\u539f\u7406...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-199645","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199645","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=199645"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199645\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199645"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199645"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199645"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}