isEven
Given a number, return true if it is even, otherwise return false.
Examples
isEven(4) → true
isEven(7) → false
Starter code
function isEven(num) {
}
Complexity of the optimal solution
Time O(1), space O(1). The modulo operator (%) is a single, constant-time arithmetic operation. The function's execution time is not dependent on the magnitude of the input number.