How to find the Largest Difference in an Array

After some attempts, I end up with this:

int iMax = N - 1;
int min = int.MaxValue, max = int.MinValue;
for (int i = 0; i < iMax; i++) {
    if (min > A[i]) min = A[i];                                     
    if (max < A[N - i - 1]){
      iMax = N - i - 1;
      max = A[iMax];
    }        
 }
 int largestDiff = max - min;

NOTE: I have just tested it with some cases. Please if you find any case in which it doesn't work, let me know in the comment. I'll try to improve it or remove the answer. Thanks!

The following code runs in O(n) and should conform to the specification (preliminary tests on codility were successful):

public int solution(int[] A)
{
    int N = A.Length;
    if (N < 1) return 0;

    int max = 0;
    int result = 0;

    for(int i = N-1; i >= 0; --i)
    {
        if(A[i] > max)
            max = A[i];

        var tmpResult = max - A[i];        
        if(tmpResult > result)
            result = tmpResult;
    }

    return result;
}

Update:
I submitted it as solution and it scores 100%.

Update 02/26/16:
The original task description on codility stated that "each element of array A is an integer within the range [0..1,000,000,000]."
If negative values would have been allowed as well, the code above wouldn't return the correct value. This could be fixed easily by changing the declaration of max to int max = int.MinValue;

Here is the O(n) Java implementation

public static int largestDifference(int[] data) {
    int minElement=data[0], maxDifference=0;

    for (int i = 1; i < data.length; i++) {
        minElement = Math.min(minElement, data[i]);
        maxDifference = Math.max(maxDifference, data[i] - minElement);
    }
    return maxDifference;
}