HDU 1381 Crazy Search

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 using namespace std;
 5 const int maxn = 16000010;
 6 int bs[256],cnt,n,base,ans,T;
 7 char str[1000010];
 8 bool hs[maxn];
 9 int main() {
10     scanf("%d",&T);
11     while(T--) {
12         scanf("%d%d%s",&n,&base,str);
13         int len = strlen(str);
14         memset(hs,false,sizeof(hs));
15         for(int i = cnt = 0; i < len; ++i)
16             if(!bs[str[i]]) {
17                 bs[str[i]] = cnt++;
18                 if(cnt == base) break;
19             }
20         for(int i = ans = 0; i + n <= len; ++i) {
21             unsigned int hashV = 0;
22             for(int j = 0; j < n; j++)
23                 hashV = hashV*base + bs[str[i+j]];
24             if(!hs[hashV]) {
25                 hs[hashV] = true;
26                 ans++;
27             }
28         }
29         printf("%d\n",ans);
30         if(T) puts("");
31     }
32     return 0;
33 }