200329题（寻找峰值（二分法））

class Solution {
public:
	//思路：二分查找
	int findPeakElement(vector<int>& nums) {
		if (nums.size() == 0)return -1;
		int start = 0, end = nums.size() - 1;
		while (start < end)
		{
			int mid = start + (end - start) / 2;
			if (nums[mid] > nums[mid + 1])
				end = mid;//mid本身也可能是峰值
			else
				start = mid + 1;
		}
		return start;

	}
};