Trie树的简单介绍和应用
简单介绍http://www.cnblogs.com/cherish_yimi/archive/2009/10/12/1581666.html
应用http://www.cnblogs.com/cherish_yimi/archive/2009/10/12/1581795.html
1 #include <iostream> 2 #include <string> 3 #include <vector> 4 #include <cstdlib> 5 #include <map> 6 #include <list> 7 #include <algorithm> 8 #include <cstring> 9 #include <string.h> 10 11 using namespace std; 12 13 const int branchNum = 26; //声明常量 14 int i; 15 16 struct Trie_node { 17 bool isStr; //记录此处是否构成一个串。 18 Trie_node *next[branchNum]; //指向各个子树的指针,下标0-25代表26字符 19 Trie_node() : 20 isStr(false) { 21 for (int i = 0; i < branchNum; i++) 22 next[i] = NULL; 23 } 24 }; 25 26 class Trie { 27 public: 28 Trie(); 29 void insert(const char* word); 30 bool search(char* word); 31 void deleteTrie(Trie_node *root); 32 bool pre_char(bool judge, Trie_node* top); 33 public: 34 Trie_node* root; 35 }; 36 37 Trie::Trie() { 38 root = new Trie_node(); 39 } 40 41 void Trie::insert(const char* word) { 42 Trie_node *location = root; 43 while (*word) { 44 if (location->next[*word - 'a'] == NULL) //不存在则建立 45 { 46 Trie_node *tmp = new Trie_node(); 47 location->next[*word - 'a'] = tmp; 48 } 49 location = location->next[*word - 'a']; //每插入一步,相当于有一个新串经过,指针要向下移动 50 word++; 51 } 52 location->isStr = true; //到达尾部,标记一个串 53 } 54 55 bool Trie::search(char *word) { 56 Trie_node *location = root; 57 while (*word && location) { 58 location = location->next[*word - 'a']; 59 word++; 60 } 61 return (location != NULL && location->isStr); 62 } 63 64 void Trie::deleteTrie(Trie_node *root) { 65 for (i = 0; i < branchNum; i++) { 66 if (root->next[i] != NULL) { 67 deleteTrie(root->next[i]); 68 } 69 } 70 delete root; 71 } 72 73 bool Trie::pre_char(bool judge, Trie_node* top) { 74 bool tmpjud, res; 75 res = false; 76 if (top->isStr && judge) 77 return true; 78 tmpjud = judge || top->isStr; 79 for (int i = 0; i < branchNum; i++) { 80 if (top->next[i] != NULL) 81 res = res || pre_char(tmpjud, top->next[i]); 82 } 83 return res; 84 } 85 86 int main() //简单测试 87 { 88 Trie t; 89 t.insert("a"); 90 t.insert("abandon"); 91 char * c = "abandoned"; 92 t.insert(c); 93 t.insert("abashed"); 94 if (t.search("abashed")) 95 cout << "true\n"; 96 if (t.pre_char(false, t.root)) 97 cout << "yes\n"; 98 else 99 cout << "no\n"; 100 return 0; 101 }