136. Single Number leetcode solution in c++

int singleNumber(vector<int>& nums) {
    int result = 0;
    for (int num : nums) {
        result ^= num;
    }
    return result;
}

Explanation: - We start by initializing the variable result to 0. This variable will store the single number that appears only once in the given vector of integers. - We iterate through each number num in the nums vector using a range-based for loop. - Inside the loop, we use the XOR (^) operator to update the result variable. The XOR operation returns 1 if the corresponding bits of two operands are different, and 0 otherwise. By XORing all the numbers in the vector, the duplicate numbers will cancel each other out, leaving only the single number in the result variable. - Finally, we return the result variable, which now contains the single number that appears only once in the given vector.

Example: Suppose we have the input vector nums = {2, 3, 2, 4, 4}. We can visualize the XOR operation for each number in the vector as follows:

0 ^ 2 = 2
2 ^ 3 = 1
1 ^ 2 = 3
3 ^ 4 = 7
7 ^ 4 = 3

The final value of result is 3, which is the single number that appears only once in the vector.