int SearchMaximum(int []arry){
        int start = 0, end = arry.length-1,mid;
        if(arry.length==0||arry==null) return -1;
        while(start+1<end){
            mid=start+(end-start)/2;
            if(arry[mid]>=arry[mid+1]){
                end = mid;
            }else {
                start =mid;
            }
        }
        return Math.max(arry[end], arry[start]);
    }