Description

You have just moved from Waterloo to a big city. The people here speak an incomprehensible dialect of a foreign language. Fortunately, you have a dictionary to help you understand them.

Input

Input consists of up to 100,000 dictionary entries, followed by a blank line, followed by a message of up to 100,000 words. Each dictionary entry is a line containing an English word, followed by a space and a foreign language word. No foreign word appears more than once in the dictionary. The message is a sequence of words in the foreign language, one word on each line. Each word in the input is a sequence of at most 10 lowercase letters.

Output

Output is the message translated to English, one word per line. Foreign words not in the dictionary should be translated as “eh”.

Sample Input

dog ogday
cat atcay
pig igpay
froot ootfray
loops oopslay

atcay
ittenkay
oopslay

Sample Output

cat
eh
loops

題目大意

在給出字典資料時，由後邊的數查詢前面的數，然後給出檢索條目，輸出查詢結果，若字典中不存在，輸出“eh”。

實現方法

1、STL

C++能過，G++TLE

#include <iostream>
#include<cstdio>
#include<string>
#include<map>
using namespace std;
map<string,bool>exi;
map<string,string>mp;
int main()
{
    char str1[11],str2[11];
    char t;
    while(true)
    {
        if((t=getchar())=='\n'
 
)
            break;
        str1[0]=t;
        int i=1;
        while(true)
        {
            t=getchar();
            if(t==' ')
            {
                str1[i]='\0';
                break;
            }
            else
                str1[i++]=t;
        }
        cin>>str2;
        getchar();
        mp.insert(make_pair<string,string>(str2,str1));
        exi.insert(make_pair<string,bool>(str2,true));
    }
    while(cin>>str1)
    {
        if(exi[str1])
            cout<<mp[str1]<<endl;
        else
            cout<<"eh"<<endl;
    }
    return 0;
}

2、二分

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
#define maxn 100007
#define maxl 17
struct node
{
    char str1[maxl];
    char str2[maxl];
}s[maxn];
int num=0;
bool cmp(node x,node y)
{
    return strcmp(x.str2, y.str2) < 0;
}
int binary_find(char *str)
{
    int l=0,r=num-1;
    while(l<=r)
    {
        int m=(l+r)/2;
        if(strcmp(s[m].str2,str)==0)
            return m;
        if(strcmp(s[m].str2,str)<0)
            l=m+1;
        else if(strcmp(s[m].str2,str)>0)
            r=m-1;
    }
    return -1;
}

int main()
{
    char str[maxl*2];
    while(true)
    {
        gets(str);
        if(str[0] == '\0')
            break;
        sscanf(str,"%s %s", s[num].str1, s[num].str2);
        num++;
    }
    sort(s,s+num,cmp);
    while(gets(str)!=NULL)
    {
        if(str[0] == '\0')
            break;
        int ans=binary_find(str);
        if(ans==-1)
            printf("eh\n");
        else
            printf("%s\n",s[ans].str1);
    }
    return 0;
}

3、字典樹

#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
#define maxl 17
#define maxn 100007
char str[maxl*2],ans[maxl],str1[maxl],str2[maxl];
struct trie
{
    char aim[maxl];
    trie *ne[27];
}*root;
trie *create()
{
    trie *p=new trie;
    for(int i=0;i<27;i++)
        p->ne[i]=NULL;
    strcpy(p->aim,"eh");
    return p;
}
void make_tree(trie *p,char *s,char *e)
{
    int len=strlen(s),k;
    for(int i=0;i<len;i++)
    {
        k=s[i]-'a';
        if(p->ne[k]==NULL)
            p->ne[k]=create();
        p=p->ne[k];
    }
    strcpy(p->aim,e);
}
void find_str(trie *p,char *f)
{
    int len=strlen(f),k;
    for(int i=0;i<len;i++)
    {
        k=f[i]-'a';
        if(p->ne[k]==NULL)
        {
            strcpy(ans,"eh");
            break;
        }
        p=p->ne[k];
    }
    strcpy(ans,p->aim);
}
int main()
{
    root=create();
    int i=0;
    while(true)
    {
        gets(str);
        if(str[0] == '\0')
            break;
        sscanf(str,"%s %s", str1, str2);
        make_tree(root,str2,str1);
        i++;
    }
    while(gets(str)!=NULL)
    {
        if(str[0] == '\0')
            break;
        find_str(root,str);
        printf("%s\n",ans);
    }
    return 0;
}

4、雜湊

ELFHash演算法

unsigned int ELFHash(char *str)  
{  
    unsigned int hash = 0;  
    unsigned int x = 0;  

    while (*str)  
    {  
        hash=(hash << 4);//將hash左移4位，等價於*16
        hash = hash + (*str);
        //加上當前字元位的ASCII碼，即把當前字元ASCII存入hash低四位。   
        if ((x = hash & 0xF0000000L) != 0)   
        //取hash的高四位並賦值給x,如果不為0，則表明字串的長度大於7，現在正在往hash中存入第7個字元，
        //如果再不處理，在新增下一個字元hash左移4位時，曾存入的第一個字元（高4位）就將被移出，造成資訊丟失
        {    
            hash ^= (x >> 24);  
            //將hash的高四位與hash的低5~8位進行異或（算是通過影響5~8位來實現對資訊的一種儲存方式吧<個人理解>），
            //因為hash低1~4剛剛存入了新的字元，所以是右移24位
            //x右移24位時，如果最高的那一位為0，只會影響hash的5-8位，否則會影響5-31位，因為C語言使用的算數移位，
            //最高位為1導致x右移時，會在前面補1 
            hash &= ~x;   //對hash的最高4位（28~31）清零，用於實現對下一個字元的存入
        }  
        str++;  //遍歷下一個字元
    }  
    return (hash & 0x7FFFFFFF);    
    //如果最後結果是負數，處理為非負數，即捨棄最高位（當處理字串時，只有字元不可能為負值）
}  

程式碼實現

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
#define maxn 100007
#define maxl 17
const int mod = maxn;
int hashTable[mod];
int countt;
char ans[maxl];
struct HashNode
{
    char str1[maxl];
    char str2[maxl];
    int next;
};
HashNode h[maxn];
void init_Hash()
{
    for (int i = 0; i < mod; i++)
    {
        hashTable[i] = -1;
    }
    countt = 0;
}
int ELFhash(char *str)
{
    unsigned long hash = 0;
    unsigned long x = 0;
    while (*str)
    {
        hash = (hash << 4) + (*str++);
        if ((x = hash & 0xF0000000L) != 0)
        {
            hash ^= (x >> 24);
            hash &= ~x;
        }
    }
    return hash % mod;
}
void insert_Hash(char str1[],char str2[])
{
    int value = ELFhash(str2);
    strcpy(h[countt].str1,str1);
    strcpy(h[countt].str2,str2);
    h[countt].next = hashTable[value];
    hashTable[value] = countt;
    countt++;
}
bool search_Hash(char str[])
{
    int value = ELFhash(str);
    int next = hashTable[value];
    while (next != -1)
    {
        if (strcmp(str, h[next].str2) == 0)
        {
            strcpy(ans,h[next].str1);
            return true;
        }
        next = h[next].next;
    }
    return false;
}
int main()
{
    init_Hash();
    char str1[maxl],str2[maxl];
    char str[maxl*2];
    while(true)
    {
        gets(str);
        if(str[0] == '\0')
            break;
        sscanf(str,"%s %s", str1, str2);
        insert_Hash(str1,str2);
    }
    while (gets(str)!=NULL)
    {
        if(str[0] == '\0')
            break;
        if (search_Hash(str))
            printf("%s\n",ans);
        else
            printf("eh\n");
    }
    return 0;
}