Given two integers x and y, return the sum of the two integers without using the operators + and -.
Example 1
Input: x = 1, y = 2
Output: 3
Explanation: In binary 1 = 01 and 2 = 10. They share no set bits, so XOR alone gives 11 = 3 with no carry.
Example 2
Input: x = 2, y = 3
Output: 5
Explanation: 2 + 3 = 5. XOR gives the bits without carries (10 ^ 11 = 01), and AND shifted left gives the carry (10 << 1 = 100). Adding those two again gives 101 = 5.
Example 3
Input: x = -1, y = 1
Output: 0
Explanation: -1 and 1 cancel out, so the sum is 0.
Binary addition splits into two parts: the sum of bits ignoring carries (XOR) and the carries themselves (AND shifted left). Repeat until there is no carry left.
Run checks all cases above. Submit evaluates all test cases.