[codility]Abs-distinct

// you can also use includes, for example:
// #include <algorithm>
int solution(const vector<int> &A) {
    // write your code in C++98
    //...traverse the array from both direction, and move according to the 
    //absolute value
    int result = 0;
    long long prevAbsoluteValue = -1;
    for(int i = 0, j = A.size()-1; i <= j; )
    {
        long long absValueLeft = A[i];
        //we need use llabs to get the absolute value of long long instead of abs
        //to avoid overflow
        absValueLeft = llabs(absValueLeft);
        long long absValueRight = A[j];
        absValueRight = llabs(absValueRight);
        long long absBiggerNumber = max(absValueLeft, absValueRight);
        
        if(absValueLeft > absValueRight) i++;
        else j--;
        
        if(prevAbsoluteValue != absBiggerNumber) result++;
        prevAbsoluteValue = absBiggerNumber;
    }
    //...return result
    return result;
}