Greater power
Easy Accuracy: 0.0% Submissions: 10 Points: 2

Given four integers a, b, m, n . Find whether  pow(a,b) is greater than pow(m,n) or not. Where pow(x,y) denotes x raised to the power y. Output 1 if pow(a,b) is greater, output 0 if pow(m,n) is greater otherwise output -1 if both are equal.

Example 1:

Input:
a = 2 , b = 2 , m = 3 , n = 2
Output:
0
Explanation:
22 = 4, and 32 = 9. 9>4. So,
the Output 0.

Example 2:

Input:
a = 1 , b = 23 , m = 1 , n = 989
Output:
-1
Explanation:
Both 123 and 1989 = 1. So,
the Output is -1. 

You don't need to read input or print anything. Your task is to complete the function greaterPower() which takes 4 Integers a,b,m and n as input and returns the answer.

Expected Time Complexity: O(max(log(a),log(m))
Expected Auxiliary Space: O(1)

Constraints:
0 <= b,n <= 1018
1 <= a,m <= 1018