The single number array appears once in addition to an element, and the other occurs two times to find the element

Given an array of integers, every element appears twice except for one. Find the single one.

Note:
Your algorithm should has a linear runtime complexity. Could you implement it without using extra memory?

In the array, except one element appears once, the other appears two times to find the element that appears only once.

A number and an XOR result of 0, a number with 0 XOR result also for its own

For example arrays: [6,6,3], 6 and 6 Xor are 0,0 with 3 XOR or 3, so all elements in an array will be the final result:

1  Public classSolution {2      Public intSinglenumber (int[] A) {3         4          intn =a.length;5          intresult = 0;6          7           for(inti = 0; I < n; i + +)8Result ^=A[i];9             Ten          returnresult; One     } A}

The single number array appears once in addition to an element, and the other occurs two times to find the element