HDOJ 1251 -- 统计难题 Trie
Trie的写法是很灵活的，感觉跟segment tree一样，要活用
1 /* 2 PROG: 统计难题 3 ID : ouyangyewei 4 LANG: C++ 5 */ 6 #include <string> 7 #include <cstdio> 8 #include <cstdlib> 9 #include <memory.h> 10 #include <iostream> 11 #include <algorithm> 12 using namespace std; 13 14 struct Trie_Node 15 { 16 int cnt; 17 Trie_Node *branch[27]; 18 Trie_Node():cnt( 0 ) 19 { 20 memset( branch, 0, sizeof(branch) ); 21 }// Init 22 }; 23 24 class Trie 25 { 26 public: 27 Trie(); 28 void Trie_Insert( char ss[] ); 29 int Trie_Find( char ss[] ); 30 31 private: 32 Trie_Node *root; 33 }t; 34 35 Trie::Trie() 36 { 37 root = new Trie_Node(); 38 }// Trie 39 40 void Trie::Trie_Insert( char ss[] ) 41 { 42 Trie_Node *ptr = root; 43 Trie_Node *temp = NULL; 44 int slen = strlen( ss ); 45 for ( int i=0; i<slen ;++i ) 46 { 47 if ( ptr->branch[ ss[i]-'a' ]==NULL ) 48 { 49 temp = new Trie_Node(); 50 ptr->branch[ ss[i]-'a' ] = temp; 51 } 52 53 ++( ptr->branch[ ss[i]-'a' ]->cnt ); 54 ptr = ptr->branch[ ss[i]-'a' ]; 55 }// Insert 56 57 return ; 58 }// Trie_Insert 59 60 int Trie::Trie_Find( char ss[] ) 61 { 62 int i, slen = strlen( ss ); 63 Trie_Node *ptr = root; 64 for ( i=0; i<slen; ++i ) 65 { 66 ptr = ptr->branch[ ss[i]-'a' ]; 67 if ( ptr==NULL ) break; 68 } 69 70 if ( i==slen ) 71 return ( ptr->cnt ); 72 else 73 return 0; 74 }// Trie_Find 75 76 int main() 77 { 78 char vocabu[12]; 79 while ( gets( vocabu ) ) 80 { 81 if ( !strcmp( vocabu, "" ) ) break; 82 t.Trie_Insert( vocabu ); 83 }// creat the trie 84 85 while ( EOF != scanf("%s", vocabu) ) 86 { 87 printf("%d\n", t.Trie_Find( vocabu )); 88 }// Find the prefix 89 90 return 0; 91 }
