题解 | #判断一个链表是否为回文结构#

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) {
        // write code here
        int l = 0;
        int r = nums.size()-1;
        int len =nums.size();
        while(l<=r) {
            int mid = (l+r)/2;
            if ((mid>=len-1 || nums[mid]>nums[mid+1])&&(mid==0 || nums[mid]>nums[mid-1])) {
                return mid;
            }
            if (nums[l]>nums[mid]) {
                r= mid-1;
            }
            else if (nums[r]>nums[mid]) {
                l = mid+1;
            } else if (nums[mid]>nums[mid-1]) {
                l = mid+1;
            }
            else {
                r = mid-1;
            }
        }
        return l;
    }
};