553. Optimal Division 最佳分割

Given a list of positive integers, the adjacent integers will perform the float division. For example, [2,3,4] -> 2 / 3 / 4.

However, you can add any number of parenthesis at any position to change the priority of operations. You should find out how to add parenthesis to get the maximum result, and return the corresponding expression in string format. Your expression should NOT contain redundant parenthesis.

Example:

Input: [1000,100,10,2]
Output: "1000/(100/10/2)"
Explanation:
1000/(100/10/2) = 1000/((100/10)/2) = 200
However, the bold parenthesis in "1000/((100/10)/2)" are redundant, 
since they don't influence the operation priority. So you should return "1000/(100/10/2)". 

Other cases:
1000/(100/10)/2 = 50
1000/(100/(10/2)) = 50
1000/100/10/2 = 0.5
1000/100/(10/2) = 2

Note:

1. The length of the input array is [1, 10].
2. Elements in the given array will be in range [2, 1000].
3. There is only one optimal division for each test case.

给定一个正整数的列表，相邻的整数将执行浮点划分。例如，[2,3,4]→2/3/4。 但是，您可以在任何位置添加任意数量的括号来更改操作的优先级。您应该找出如何添加括号以获取最大结果，并返回字符串格式的相应表达式。您的表达式不应包含冗余圆括号。

class Solution(object):
    def optimalDivision(self, nums):
        """
        :type nums: List[int]
        :rtype: str
        """
        A = map(str, nums)
        if len(A) <= 2:
            return '/'.join(A)
        return A[0] + '/(' + '/'.join(A[1:]) + ')'

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