题解 | #寻找峰值#

class Solution {
  public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param nums int整型vector
     * @return int整型
     */
    int findPeakElement(vector<int>& nums) {
        int len = nums.size();
        if (len == 0) return -1; //不存在峰值
        if (len == 1) return 0;

        int left = 0;
        int right = len - 1;
        int mid = right/ 2;

        if (nums[0] > nums[1]) return 0;

        if (nums[len - 1] > nums[len - 2]) return len - 1;

        while (true) {
            if (nums[mid - 1] < nums[mid] && nums[mid] > nums[mid + 1]) return mid;

            if (nums[mid - 1] < nums[mid] && nums[mid] <= nums[mid + 1]) {
                left = mid + 1;
                mid = (right+left)/2;
                continue;
            }

            if (nums[mid - 1] >= nums[mid] && nums[mid] > nums[mid + 1]) {
                right = mid;
                mid = (right+left)/2;
                continue;
            }
        }

    }
};