Given two integers a and b, use XOR to decide whether they have opposite signs (one strictly negative and the other non-negative). Return true if the signs differ, otherwise false. Zero counts as non-negative.
Input: A JSON object {"a": <integer>, "b": <integer>}.
Output: Return true if a and b have opposite signs, otherwise false.
Input: {"a":3,"b":-4}
Output: true
Explanation: Different signs -> true.Input: {"a":3,"b":4}
Output: false
Explanation: Both non-negative -> false.-10^9 <= a, b <= 10^9