题解 | #最长山脉#

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 longestmountain(vector<int>& nums, int begin = 0) {
        // write code here
        int len = 2;
        int res = 0;
        int flag = 0;

        for (int i = begin; i < nums.size() - 1; ++i) {
            if (!flag) {
                if (nums[i + 1] > nums[i]) {
                    flag = 1;
                    --i;
                    continue;
                }
            }

            if (flag == 1) {
                if (nums[i + 1] > nums[i]) {
                    ++len;
                } else if (nums[i + 1] == nums[i]) {
                    return max(res, longestmountain(nums, i + 1));
                } else if (nums[i + 1] < nums[i]) {
                    flag = 2;
                    --i;
                    res = len;
                    continue;
                }

            }

            if (flag == 2) {
                if (nums[i + 1] < nums[i]) {
                    ++res;
                } else {
                    return max(res - 1, longestmountain(nums, i ));
                }
            }
        }

        // if (flag == 0 || flag == 1)return 0;
        return res;
    }
};