POJ - 2503
这题用map做时有2100ms，而用字典树去做时360ms就过了。
map的
字典树的：
下面是代码：
1 #include<iostream> 2 #include <stdio.h> 3 #include <map> 4 using namespace std; 5 int main() 6 { 7 char str[50],h[50]; 8 string tp; 9 int count=1; 10 map<string,string>dic; 11 while(true){ 12 char c; 13 if((c=getchar())=='\n')break; 14 else 15 { 16 str[0]=c; 17 int i=1; 18 while(true) 19 { 20 c=getchar(); 21 if(c==' ') 22 { 23 str[i]='\0'; 24 break; 25 } 26 else str[i++]=c; 27 } 28 } 29 scanf("%s",h); 30 getchar(); 31 dic[h]=str; 32 count++; 33 } 34 string tar; 35 while(cin>>tar) 36 { 37 map<string,string>::iterator p=dic.find(tar); 38 if(p==dic.end()) 39 printf("%s\n","eh"); 40 else cout << (*p).second << endl; 41 } 42 return 0; 43 }
1 #include <iostream> 2 #include <stdio.h> 3 #include <stdlib.h> 4 #include <string.h> 5 using namespace std; 6 char str[50],str1[50]; 7 8 struct Nod{ 9 char str[50]; 10 Nod*next[26]; 11 Nod(){ 12 for(int i = 0; i < 26; i ++){ 13 next[i] = NULL; 14 } 15 } 16 }t; 17 18 void mkTrie(char *s, char *ss){ 19 Nod *p = &t; 20 for(int i = 0; ss[i]; i ++){ 21 int a = ss[i] - 'a'; 22 if(p->next[a]==NULL){ 23 p->next[a] = new Nod; 24 } 25 p = p->next[a]; 26 } 27 strcpy(p->str,s); 28 } 29 30 void find(char *s){ 31 Nod *p = &t; 32 for(int i = 0; s[i]; i ++){ 33 int a = s[i]-'a'; 34 if(p->next[a] ==NULL){ 35 puts("eh"); 36 return; 37 } 38 p = p->next[a]; 39 } 40 puts(p->str); 41 } 42 int main(){ 43 char c; 44 while(1){ 45 if((c=getchar())=='\n')break; 46 str[0] = c; 47 int i = 1; 48 while(1){ 49 if((c=getchar())==' ')break; 50 str[i++] = c; 51 } 52 str[i] = '\0'; 53 i = 0; 54 while(1){ 55 if((c=getchar())=='\n')break; 56 str1[i++] = c; 57 } 58 str1[i] = '\0'; 59 mkTrie(str,str1); 60 } 61 while(scanf("%s",str)!=EOF){ 62 find(str); 63 } 64 return 0; 65 }
