162 Find Peak Element

public class Solution {
    public int findPeakElement(int[] nums) {
        if (nums == null || nums.length == 0 || nums.length == 1) {
            return 0;
        }
        
        int l = 0;
        int r = nums.length - 1;
        while (l <= r) {
            if (l == r) return l;
            int mid = (l+r)/2;

            if (nums[mid] < nums[mid + 1]) {
                l = mid +1;
            } else {
                r = mid;
            }
        }
        return l;
    }
}

用二分法 可是自己写边界写错了！！！