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

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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; }