"From zero single Brush Leetcode"

Yes, I'm Wu. 2009 fans, from today, imitate the "from zero single row" series, Vegetable chicken single brush leetcode!

Topic:

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

Answer:

is actually looking for different. This problem requires a more trick idea: bitwise arithmetic .

Imagine, any two of the same number, to do the XOR or operation answer is what? is 0. 4^8^4^8 = 0. The same is true for N-bits in the middle.

0 with any number of different or operation, what is the answer? is not this number itself.

Class Solution {public:    int singlenumber (int a[], int n) {        int sum = a[0];        for (int i = 1; i<n; i++)            sum = sum ^ a[i];        return sum;    }};

"From zero single Brush Leetcode"