HDOJ 1075 -- What Are You Talking About Trie( STL )

方法一：Trie

思路：

1. 开辟一个结构体数组dict，数组中存放索引值和索引，比如from fiwo

2. 建立一颗Trie，Trie维护 整型变量 index，结构体指针数组 branch，在建立Trie的过程中，若是单词结尾，Trie中index赋值为dict的索引，否则为-1



写法一：string类降低编码复杂度，当然代价是时间复杂度加大约 2 倍

/*
 PROG:   What Are You Talking About
 ID  :   
 LANG:   C++
 */
 #include <map>
 #include <string>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
 #include <memory.h>
 #include <algorithm>
 using namespace std;
 
 struct Dictionary
 {
     string front, back;
 }dict[500004];
 
 struct Trie_Node
 {
     int index;
     Trie_Node *branch[27];
     Trie_Node(): index( -1 )
     {
         memset( branch, 0, sizeof(branch) );
     }
 };
 class Trie
 {
     public:
         Trie();
         ~Trie() { }
         void Trie_Insert( int k, string ss );
         int Trie_Find( string ss );
         
     private:
         Trie_Node *root;
 }t;
 
 /* Valiable */
 int M=0;
 
 Trie::Trie()
 {
     root = new Trie_Node();
 }// Trie
 
 void Trie::Trie_Insert( int k, string ss )
 {
     Trie_Node *ptr = root;
     int slen = ss.length();
     for ( int i=0; i<slen; ++i )
     {
         if ( ptr->branch[ ss[i]-'a' ]==NULL )
         {
             Trie_Node *temp = new Trie_Node();
             ptr->branch[ ss[i]-'a' ] = temp;
         }
     
         ptr = ptr->branch[ ss[i]-'a' ];
     }
     
     ptr->index = k;
 }// Trie_Insert
 
 int Trie::Trie_Find( string ss )
 {
     Trie_Node *ptr = root;
     int slen = ss.length();
     for ( int i=0; i<slen; ++i )
     {
         if ( ptr->branch[ ss[i]-'a' ]!=NULL )
             ptr = ptr->branch[ ss[i]-'a' ];
         else
             return -1;
     }
     
     return ptr->index;
 }// Trie_Find
 
 void ReadData()
 {
     string s1, s2;
     
     cin >> s1;   // Words " START "
     while ( cin >> s1 && s1!="END" )
     {
         cin >> s2;
         dict[M].front = s1;
         dict[M].back = s2;
         
         t.Trie_Insert( M++, s2 );   // Note " M++ "
     }// dictionary
 }// ReadData
 
 void Solve()
 {
     int  slen, kk;
     string words, line;
     
     cin >> line;  // Words " START "
     getchar();
     while ( getline( cin, line ) && line!="END" )
     {
         words = "";
         slen = line.length();
         for ( int i=0; i<slen; ++i )
         {
             if ( isalpha( line[i] ) )
             {
                 words += line[i];
             }
             else
             {
                 kk = t.Trie_Find( words );
                 if ( kk==-1 )
                     cout << words;
                 else
                     cout << dict[kk].front;
                 cout << line[i];
                 
                 words = "";
             }
         }// scanning
         
         cout << endl;
     }// books
 }// Solve
 
 int main()
 {
     ReadData();
     Solve();
     
     return 0;
 }

写法二：C语言的写法，编码复杂度加大，时间复杂度尚可，250MS

View Code 
 /*
 PROG:   What Are You Talking About
 ID  :   
 LANG:   C++
 */
 #include <map>
 #include <string>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
 #include <memory.h>
 #include <algorithm>
 using namespace std;
 
 const int maxn = 15;
 
 struct Dictionary
 {
     char front[maxn];
     char back[maxn];
 }dict[500004]; 
 
 struct Trie_Node
 {
     int index;
     Trie_Node *branch[27];
     Trie_Node(): index( -1 )
     {
         memset( branch, 0, sizeof(branch) );
     }
 };
 class Trie
 {
     public:
         Trie();
         ~Trie() { }
         void Trie_Insert( int k, char ss[] );
         int Trie_Find( char ss[] );
         
     private:
         Trie_Node *root;
 }t;
 
 /* Valiable */
 int M=0;
 
 Trie::Trie()
 {
     root = new Trie_Node();
 }// Trie
 
 void Trie::Trie_Insert( int k, char ss[] )
 {
     Trie_Node *ptr = root;
     int slen = strlen( ss );
     for ( int i=0; i<slen; ++i )
     {
         if ( ptr->branch[ ss[i]-'a' ]==NULL )
         {
             Trie_Node *temp = new Trie_Node();
             ptr->branch[ ss[i]-'a' ] = temp;
         }
     
         ptr = ptr->branch[ ss[i]-'a' ];
     }
     
     ptr->index = k;
 }// Trie_Insert
 
 int Trie::Trie_Find( char ss[] )
 {
     Trie_Node *ptr = root;
     int slen = strlen( ss );
     for ( int i=0; i<slen; ++i )
     {
         if ( ptr->branch[ ss[i]-'a' ]!=NULL )
             ptr = ptr->branch[ ss[i]-'a' ];
         else
             return -1;
     }
     
     return ptr->index;
 }// Trie_Find
 
 void ReadData()
 {
     char s1[maxn], s2[maxn];
     
     scanf("%s", &s1);   // Words " START "
     while ( EOF!=scanf("%s", s1), strcmp(s1, "END")!=0 )
     {
         scanf("%s", &s2);
         strcpy( dict[M].front, s1 );
         strcpy( dict[M].back, s2 );
         
         t.Trie_Insert( M++, s2 );   // Note " M++ "
     }// dictionary
 }// ReadData
 
 void Solve()
 {
     int  slen, tlen, kk;
     char words[maxn], line[3004];
     
     scanf("%s", line);  // Words " START "
     getchar();
     while ( gets( line ), strcmp( line, "END" )!=0 )
     {
         tlen = 0;
         slen = strlen( line );
         memset( words, 0, sizeof(words) );
         
         for ( int i=0; i<slen; ++i )
         {
             if ( isalpha( line[i] ) )
             {
                 words[ tlen++ ] = line[i];
             }
             else
             {
                 kk = t.Trie_Find( words );
                 if ( kk==-1 )
                     printf("%s", words);
                 else
                     printf("%s", dict[kk].front);
                 printf("%c", line[i]);
                 
                 tlen = 0;
                 memset( words, 0, sizeof(words) );
             }
         }// scanning
         
         printf("\n");
     }// books
 }// Solve
 
 int main()
 {
     ReadData();
     Solve();
     
     return 0;
 }

方法二：STL MAP

编码复杂度低，时间复杂度差

/*
 PROG:   What Are You Talking About
 ID  :   
 LANG:   C++
 */
 #include <map>
 #include <string>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
 #include <memory.h>
 #include <algorithm>
 using namespace std;
 
 int slen;
 string s1, s2, line, result;
 map <string, string> data;
 
 int main()
 {    
     cin >> s1;   // START
     while ( cin >> s1, s1!="END" )
     {
         cin >> s2;
         data[ s2 ] = s1;
     }// dictionary
     
     cin >> s1;
     getchar();  // fetch carry reture
     while ( getline( cin, line ) && line!="END" )
     {
         result = "";
         slen = line.length();
         for ( int i=0; i<slen; ++i )
         {
             if ( isalpha( line[i] ) )
             {
                 result += line[i];
             }
             else
             {
                 if ( data[ result ]=="" )
                     cout << result;
                 else
                     cout << data[ result ];
                 cout << line[i];
                 
                 result = "";
             }
         }// scanning
         
         cout << endl;
     }// books
     
     return 0;
 }