Single Number

A simple solution, using 2 properties of XOR: A ⊕ A = 0 and B ⊕ 0 = B In other words, A ⊕ A ⊕ B = B

class Solution {
    public int singleNumber(int[] nums) {
        
        
        for(int i = 0; i< nums.length-1; i++){
            nums[i+1] ^= nums[i];
        }
        
        return nums[nums.length-1];
    }
}