Given a sorted, shifted array find the minimum element

Given a sorted, shifted array find the minimum element. For example in {3,4,5,1,2} the minimum is 1, in {4,5,1,2,3} the minimum is 1.

Concept of Binary search can be use with little modification.

// finds the smallest number and returns
// it , if not found it returns -1
public static int findSmallest(int a[], int N)
{
    if(length==0 || a==NULL)
        return -1;

    int start=0,end=N-1;

    while(start <= end)
    {
        int mid=(start end)/2;

        // this is the standard comparison condition
        if(a[mid] > a[mid+1])
            return a[mid+1];

        // an extra comparison that adds the optimization that 
        // if the mid element is the smallest one, there will not be 
        // extra iterations
        if(a[mid] < a[mid-1])
            return a[mid];

        // the left half is in strictly increasing order
        // so we search in the second half
        if(a[mid] > a[start])
        {
            start = mid+1;
        }
        // The array is not rrotated so we simply
        // return the first element of the array
        else if(a[mid] >= a[start] && a[mid] <= a[end])
             return a[0];

        // the right half is in strictly increasing order
        // and hence we will search in the left half
         else
           end= mid-1;

    }
    return -1;
}