目录

hash

int hash(ll x){    ll t = x % N;    while (h[t] && h[t] != x) t = (t + 1) % N;    return t;}int main(){    fo(i, 1, n)        x = (x * 26 + s[i] - 97) % mo;    t = hash(x);    h[t] = x;}

double hash

int hash(ll x, ll y){    ll t = x % N;    while (h[t][0] && (h[t][0] != x || h[t][1] != y)) t = (t + 1) % N;    return t;}int main(){    fo(i, 1, n)    {        x = (x * 26 + s[i] - 97) % mo;        y = (y * 26 + s[i] - 97) % mo1;    }    t = hash(x, y);    h[t][0] = x, h[t][1] = y;}

hash字符串中的子串

int main(){    cf[0] = 1;    fo(i, 1, n) cf[i] = cf[i - 1]  * 26;     fo(i, 1, n)        qz[i] = (qz[i - 1] * 26 + s[i] - 97) % mo;//  对于[i~j]的hash值     (qz[j] - qz[i - 1] * cf[j - i + 1] % mo + mo) % mo;}

树hash

树\(hash\)用来比较树是否同构。