Maximum Number in Mountain Sequence

Java

public class Solution {
    /**
     * @param nums a mountain sequence which increase firstly and then decrease
     * @return then mountain top
     */
    public int mountainSequence(int[] nums) {
        // Write your code here
        int l = 0, r = nums.length - 1;
        int mid = (l + r) / 2;
        
        int lst = -1;
        
        while(l < r){
            if(nums[mid] < nums[mid + 1])
                l = mid;  
            else r = mid;
            
            mid = (l + r) / 2;
            if(mid == lst){
                break;
            }
            lst = mid;
        }
        if(nums[l] > nums[r]){
            return nums[l];
        }
        else{
            return nums[r];
        }
    }
}

Python

class Solution:
    """
    @param nums: a mountain sequence which increase firstly and then decrease
    @return: then mountain top
    """
    def mountainSequence(self, nums):
        # write your code here
        left, right = 0, len(nums)-1
        while left + 1 < right:
            mid = (left + right) // 2
            if nums[mid] < nums[mid+1]:
                left = mid
            else:
                right = mid
        if nums[right] > nums[left]:
            return nums[right]
        else:
            return nums[left]