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以下是C++实现Trie树的完整示例代码,包括Trie树的构建、查找和优化功能:
cpp
class TrieNode {
public:
char* path;
vector<TrieNode> children;
bool isEnd;
private:
char path;
vector<TrieNode*> children;
bool isEnd;
};
class TrieTree {
public:
TrieTree() : root(0) {}
TrieTree() : root(0) {}
~TrieTree() {}
TrieTree() {
root = new TrieNode();
}
// 建立Trie树
void build(TrieTree& tree, const string& s) {
for (char c : s) {
TrieNode* node = tree.root;
for (char* ch : node->children) {
if (node->path.find(ch) == string::npos) {
node->children.push_back(TrieNode());
}
}
node->path += ch;
tree.root = node;
}
// 标记终止字符
node->isEnd = false;
for (char c : s) {
TrieNode* node = tree.root;
for (char* ch : node->children) {
if (node->path.find(ch) == string::npos) {
node->children.push_back(TrieNode());
}
}
node->path += ch;
tree.root = node;
}
}
// 查找字符串
string search(string s) {
string result;
TrieNode* node = root;
for (char c : s) {
for (char* ch : node->children) {
if (node->path.find(ch) != string::npos) {
node = node->children[ch];
if (node->isEnd) {
result.push_back(ch);
node = node->parent;
}
}
}
}
return result.empty() ? "无匹配" : result;
}
// 去重并排序
void optimize() {
sort(root->children.begin(), root->children.end());
for (auto& child : root->children) {
for (auto* ch : child->children) {
if (child->path.find(ch) != string::npos) {
child->children[ch] = child->children[ch]->parent;
}
}
}
}
};
假设我们有一个数据库,记录了用户最近的缓存请求。每个缓存请求是一个字符串,可能包含重复字符。使用Trie树可以高效查找最近的缓存,从而减少数据库访问次数。
以下是示例代码如何在数据库中使用Trie树进行缓存管理:
cpp
int main() {
int databasesize = 1000;
string buffer[databasesize];
int buffer_idx = 0;
// 读取缓存数据
while (database_idx < database_size) {
string query;
char* ptr = buffer[database_idx++];
while (true) {
ptr += (char*)(ptr + 1);
if (ptr >= 0) {
buffer[database_idx] = *ptr;
break;
}
// 读取空指针
if (ptr == 0) {
// 停止读取
break;
}
}
// 保存查询
buffer[database_idx] = query;
// 建立Trie树
TrieTree tree(buffer[database_idx]);
tree.build(tree.root, buffer);
// 查找最近的缓存
string result = tree.search(query);
if (!result.empty()) {
database_idx++;
}
}
return 0;
}