LL data_mod(LL A, LL B){
LL ans = 1, base = A;
while(B){
if (B & 1){
ans = ans * base % mod;
}
base = base * base % mod;
B >>= 1;
}
return ans;
}
原文：http://www.cnblogs.com/garden6zg/p/7891575.html