zoj 1507 Crazy Search

#include <iostream>#include <stdio.h>#include <cstring>using namespace std;const int N=16000005; const int NUM=300;bool hash[N];int m[NUM];char str[1000000];int main(){    int tt;    cin>>tt;    while(tt--)    {        int n,nc,i,j,sum,seed=0,ans=0;        memset(hash,false,sizeof(hash));        memset(m,0,sizeof(m));        memset(str,'',sizeof(str));        cin>>n>>nc>>str;        for(i=0; '' != str[i]; ++i)        { if(!m[str[i]])      m[str[i]]=++seed; if(seed == nc)     break;        }        int len=strlen(str);        for(i=0; i<=len-n; ++i)        { sum=0; for(j=0; j<n; ++j)      sum=sum*nc+m[str[i+j]]-1; if(!hash[sum]) {     hash[sum]=true;     ++ans; }        }       if(tt)        cout<<ans<<endl<<endl;        else        cout<<ans;    }    return 0;}