Data Structure-Trie tree

[Cpp]/********************************** * ********************** data structure: the Trie tree, also known as the word search tree or dictionary tree, is a tree structure and a variant of the hash tree. Basic principle: the core idea of the Trie tree is to change space time, the common prefix of a string is used to reduce the query time overhead to improve efficiency. Application: used to count and sort a large number of strings (but not limited to strings ), therefore, it is often used by the search engine system for text word frequency statistics. Advantage: to minimize unnecessary string comparisons, the query efficiency is higher than that of hash tables. Basic Features: (1) the root node does not contain characters. Each node except the root node only contains one character. (2) from the root node to a node, the character passing through the path is connected, it is the character string corresponding to the node. (3) The characters in all subnodes of each node are different; **************************************** ***************** **/# Include <iostream> # include <cstring> # include <cstdlib> # include <cstdio> # include <climits> # include <algorithm> using namespace std; const int MAX = 26; struct Trie // Trie node declaration {bool isStr; // mark whether a Trie * next [MAX] string is formed at the node; // a pointer array, hold pointer to each son node}; void insert (Trie * root, const char * s) // insert word s into the dictionary tree {if (root = NULL | * s = '\ 0') return; Trie * p = root; while (* s) {if (p-> next [* s-'a'] = NULL) // if the section containing this character does not exist Node {Trie * temp = new Trie; for (int I = 0; I <MAX; I ++) {temp-> next [I] = NULL ;} temp-> isStr = false; p-> next [* s-'a'] = temp; p = p-> next [* s-'a'];} else {p = p-> next [* s-'a'];} s ++; // Let the pointer s point to the next character} p-> isStr = true; // mark the end of a word here to form a string} int search (Trie * root, const char * s) // query whether a word s already exists {Trie * p = root; while (p & * s) {p = p-> next [* s-'a']; s ++;} return (p & p-> isStr); // The word exists only when it is marked as true at the end of the word} void del (Trie * r Oot) // release the heap space occupied by the entire dictionary tree {for (int I = 0; I <MAX; I ++) {if (root-> next [I]! = NULL) {del (root-> next [I]) ;}} delete root;} int main () {// freopen ("C: \ Users \ Administrator \ Desktop \ kd.txt "," r ", stdin); char s [100]; Trie * root = new Trie; for (int I = 0; I <MAX; I ++) {root-> next [I] = NULL;} root-> isStr = false; int n, m; // n is the number of words entered in the Trie tree, and m is the number of words to be searched scanf ("% d", & n); getchar (); for (int I = 0; I <n; I ++) // create a dictionary tree {scanf ("% s", s); insert (root, s );} while (~ Scanf ("% d", & m) {if (! M) break; for (int I = 0; I <m; I ++) // query {scanf ("% s", s); if (search (root, s) printf ("YES \ n"); else printf ("NO \ n");} printf ("\ n");} del (root ); // It is important to release space. return 0 ;}