Trie Trie

Trie

Trie (trie) is a multi-tree structure for fast retrieval string. Tire Each node has a plurality of character pointer, while if more scans to insert and retrieve a character string, it is directed towards the characters in the node.

 

insert

 

When you need to insert a string, we go from the root, in order to scan each character:

1. If the character points to an existing node, the node continue to go down
2. If the character point blank, create a new node, move on.

When characters in the string have been retrieved, at which the recording end node.

 

Retrieval

 

When you need to retrieve a string if there is, we go from the root, scan each character:

1. If the character point blank, then there is no end.
2. If the character points to a node, then move on.

 

When all the characters in the string to be retrieved, if the current node is a node at the end to be labeled, indicating the presence of a string, or its absence explained.

 

 1 int trie[SIZE][26], tot = 1;
 2 void insert(char* str){
 3     int len = strlen(str), p = 1;
 4     for (int k = 0; k < len; k++){
 5         int ch = str[k] - 'a';
 6         if (trie[p][ch] == 0) trie[p][ch] = ++tot;
 7         p = trie[p][ch];
 8     }
 9     end[p] = true;
10 }
11 bool search(char* str){
12     int len = strlen(str), p = 1;
13     for (int k = 0; k <= len; k++){
14         p = trie[p][str[k] - 'a'];
15         if (p == 0) return false;
16     }
17     return end[p];
18 }