First and Last Position of an Element In Sorted Array.cpp

int firstOcc(vector<int>& arr, int n, int key)
{
    int s = 0, e = n - 1;
    int mid = s + (e - s) / 2;
    int ans = -1;
    while (s <= e)
    {
        if (arr[mid] == key)
        {
            ans = mid;
            e = mid - 1;
        }
        else if (key > arr[mid]) // Right me jao
        {
            s = mid + 1;
        }
        else if (key < arr[mid]) // left me jao
        {
            e = mid - 1;
        }
        mid = s + (e - s) / 2;
    }
    return ans;
}

int lastOcc(vector<int>& arr, int n, int key)
{
    int s = 0, e = n - 1;
    int mid = s + (e - s) / 2;
    int ans = -1;
    while (s <= e)
    {
        if (arr[mid] == key)
        {
            ans = mid;
            s = mid + 1;
        }
        else if (key > arr[mid]) // Right me jao
        {
            s = mid + 1;
        }
        else if (key < arr[mid])
        {
            e = mid - 1;
        }
        mid = s + (e - s) / 2;
    }
    return ans;
}

pair<int, int> firstAndLastPosition(vector<int>& arr, int n, int k)
{
    pair<int,int> p;
    p.first = firstOcc(arr, n, k);
    p.second = lastOcc(arr, n, k);
    
    return p;
}