C++ HackerRank|AND xor OR

1. Dashboard 
2.  Data Structures 
3.  Stacks 
4.  AND xor OR

5. 1. #include <iostream>#include <stack>#include <vector>using namespace std;int main(int argc, char const *argv[]){    int n, max = 0, temp;    cin >> n;    vector<int> arr(n);    stack<int> index;    for (int i = 0; i < n; ++ i)    {        cin >> arr[i];        while (! index.empty())        {            temp = arr[i] ^ arr[index.top()]; // (((a & b) ^ (a | b)) & (a ^ b)) == a ^ b            max = max > temp ? max : temp;            if (arr[index.top()] > arr[i])            {                index.pop();            }            else            {                break;            }        }        index.push(i);    }    cout << max << endl;    return 0;}