C++-POJ2503-Babelfish[hash]

 1 #include <set>
 2 #include <map>
 3 #include <cmath>
 4 #include <queue>
 5 #include <vector>
 6 #include <cstdio>
 7 #include <cstdlib>
 8 #include <cstring>
 9 #include <iostream>
10 #include <algorithm>
11 using namespace std;
12 const int MAXN=150001;//比1e5大的质数 
13 struct node{char e[11],f[11];int next;}word[MAXN];
14 int cnt,hashHead[MAXN];char s[30];
15 
16 int ELFhash(char *key){
17     unsigned long h=0;
18     for(unsigned long g;*key;h&=~g){
19         h=(h<<4)+(*key++);
20         g=h&0Xf0000000L;
21         if(g)h^=g>>24;
22     }
23     return h%MAXN;
24 }
25 
26 void find(){
27     int hash=ELFhash(s);
28     for(int i=hashHead[hash];i;i=word[i].next)
29         if(strcmp(s,word[i].f)==0)
30             {printf("%s\n",word[i].e);return;}
31     printf("eh\n");
32 }
33 
34 int main() {
35     for(cnt=1;gets(s)&&s[0]!=‘\0‘;cnt++/*cnt++必须写在外面*/) {
36         sscanf(s,"%s%s",word[cnt].e,word[cnt].f);
37         int hash = ELFhash(word[cnt].f);
38         word[cnt].next=hashHead[hash];//挂表 
39         hashHead[hash]=cnt;
40     }
41     while(gets(s))find();
42     return 0;
43 }