towerofseven.go

package towerofsevens

/*
Task:
Find a fast way, to determine whether a number (any int32 integer) is a power of 7?

Example Input and Output:
TowerOfSevens(-7) -> false
TowerOfSevens(0) -> false
TowerOfSevens(1) -> true
TowerOfSevens(7) -> true
TowerOfSevens(49) -> true
TowerOfSevens(21) -> false
TowerOfSevens(63) -> false
*/

/*
Solution:
*/

// greatest power of seven within the range of int32
const sevenPowEleven = 1977326743

// returns whether an integer number 'n' == 7**int(x) (a positive integer power of 7)
func TowerOfSevens(n int32) bool {
	return n > 0 && sevenPowEleven%n == 0
}