HASH

struct Hash_map{    static const int mask=0x7fffff;    int p[mask+1],q[mask+1];    void clear()    {        memset(q,0,sizeof(q));    }    int& operator [](int k)    {        int i;        for(i=k&mask;q[i]&&p[i]!=k;i=(i+1)&mask);//处理hash冲突        p[i]=k;        return q[i];    }};

// BKDR Hash Function—BYVOIDunsigned int BKDRHash(char *str){    unsigned int seed = 131; // 31 131 1313 13131 131313 etc..    unsigned int hash = 0;    while (*str)    {        hash = hash * seed + (*str++);    }    return (hash & 0x7FFFFFFF);}