Peak finding algorithm

main.java

// Algorithm
// Input: Array A[n], find a peak element in araray A. The peak element is 
//not necessarily a global maxima
/*
For an element,Search(A, 0, A.length-1)
midElement=(start+end)/2
1. If (midElement==end && a[midElement]>=a[midElement-1]) || (midElement==0 && a[midElement]>=a[midElement+1]) || (A[midElement]>=A[midElement-1] && A[midElement]>=A[midElement+1])
    ----> return mid
2. else if(A[midElement-1]>A[midElement])
   -----> Search left array Search(A, sstart, midElement-1)
3. else
   -----> Search right array Search(A, midElement+1, end)
*/
public class Test {
    static int PeakElement(int[] a, int s, int n){

        if(s<=n){
            int mid=(s+n)/2;
            if(a[mid-1]>a[mid]){
                //System.out.println("if: "+a[mid]);
                return PeakElement(a, s, mid-1);
            }else if(a[mid]<a[mid+1]){
                //System.out.println("else: "+a[mid]);
                return PeakElement(a, mid+1, n);
            }else{
                return mid;
            }
        }
        return  -1;
    }
    public static void main(String[] args) {
        int[] a={40, 10, 120, 5, 145, 50, 65, 90, 100, 20};
        int[] b={1, 2, 3, 4, 5};
        int x=PeakElement(a, 0, a.length-1);
        System.out.println(a[x]);
    }
}