//Binary Search

   public int findPeak(int[] A) {
        int l = 0;
        int r = A.length-1;

        while (l+1<r){
             int mid = l+(r-l)/2;
            if(A[mid]<A[mid+1]){
                l=mid;
            }else{
            r=mid;
            }
        }
            return l+1;
         }

//Math
public int findPeakElement(int[] nums) {
        for(int i=1; i<nums.length;i++){
            if(nums[i]<nums[i-1]){
                return i-1;
            }
        }return nums.length-1;
    }