leetcode:数学：spuer pow（372）

class Solution {
const int base = 1337;
int powmod(int a, int k) //a^k mod 1337 where 0 <= k <= 10
{
a %= base;
int result = 1;
for (int i = 0; i < k; ++i)
result = (result * a) % base;
return result;
}
public:
int superPow(int a, vector<int>& b) {
if (b.empty()) return 1;
int last_digit = b.back();
b.pop_back();
return powmod(superPow(a, b), 10) * powmod(a, last_digit) % base;
}
};