Your task is to calculate a^b mod 1337 where a is a positive integer and b is an extremely large positive integer given in the form of an array.
Example1:
a = 2
b = [3]
Result: 8
Example2:
a = 2
b = [1,0]
Result: 1024
一刷
题解：用recursion来实现
class Solution {
private final int base = 1337;
public int superPow(int a, int[] b) {
if(b.length == 0) return 1;
int lastDigit = b[b.length-1];
int[] copyArr = Arrays.copyOf(b, b.length-1);
return powMod(superPow(a, copyArr), 10) * powMod(a, lastDigit)%base;
}
private int powMod(int a, int n){
a %= base;
int res = 1;
for(int i=0; i<n; i++){
res = (res*a)%base;
}
return res;
}
}
