POJ

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：

#include<iostream>
#include <stdio.h>
#include <map>
using namespace std;
int main()
{
    char str[50],h[50];
    string tp;
    int count=1;
    map<string,string>dic;
    while(true){
        char c;
        if((c=getchar())=='
')break;
        else
        {
          str[0]=c;
          int i=1;
          while(true)
          {
            c=getchar();
            if(c==' ')
            {
                str[i]='';
                break;
            }
            else str[i++]=c;
        }
    }
    scanf("%s",h);
    getchar();
    dic[h]=str;
    count++;
}
    string tar;
    while(cin>>tar)
    {
        map<string,string>::iterator p=dic.find(tar);
        if(p==dic.end())
           printf("%s
","eh");
        else cout << (*p).second << endl;
    }
    return 0;
}

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
using namespace std;
char str[50],str1[50];

struct Nod{
    char str[50];
    Nod*next[26];
    Nod(){
        for(int i = 0; i < 26; i ++){
            next[i] = NULL;
        }
    }
}t;

void mkTrie(char *s, char *ss){
    Nod *p = &t;
    for(int i = 0; ss[i]; i ++){
        int a = ss[i] - 'a';
        if(p->next[a]==NULL){
            p->next[a] = new Nod;
        }
        p = p->next[a];
    }
    strcpy(p->str,s);
}

void find(char *s){
    Nod *p = &t;
    for(int i = 0; s[i]; i ++){
        int a = s[i]-'a';
        if(p->next[a] ==NULL){
            puts("eh");
            return;
        }
        p = p->next[a];
    }
    puts(p->str);
}
int main(){
    char c;
    while(1){
        if((c=getchar())=='
')break;
        str[0] = c;
        int i = 1;
        while(1){
            if((c=getchar())==' ')break;
            str[i++] = c;
        }
        str[i] = '';
        i = 0;
        while(1){
            if((c=getchar())=='
')break;
            str1[i++] = c;
        }
        str1[i] = '';
        mkTrie(str,str1);
    }
    while(scanf("%s",str)!=EOF){
        find(str);
    }
    return 0;
}