字符串hash 模板

typedef long long ll;
typedef unsigned long long ull;
#define maxn 1005
struct My_Hash
{
    ull base=;
    ull p[maxn],ha[maxn];
    void Insert(char s[])
    {
        int len=strlen(s+);
        p[]=,ha[]=;
        for(int i=;i<=len;i++)
        {
            p[i]=p[i-]*base;
            ha[i]=ha[i-]*base+(ull)s[i];
        }
    }
    ull gethash(int l,int r)
    {
        return (ull)ha[r]-ha[l-]*p[r-l+];
    }
}S;
int main()
{
    char s[maxn];
    cin>>s+;
    S.Insert(s);
    int T;
    cin>>T;
    while(T--)
    {
        int l,r;
        cin>>l>>r;
        cout<<S.gethash(l,r)<<endl;
    }

    return ;
}

参考博客：链接1、链接2