題目
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:
- The length of the input array is [1, 10].
- Elements in the given array will be in range [2, 1000].
- There is only one optimal division for each test case.
難度
Medium
方法
這題難度標為Medium，但是很簡單。n1/n2/n3/n5/n5通過加括號改變運算優先級，它的最大值為n1*n3*n4*n5/n2，即n1/(n2/n3/n4/n5)。添加括號的位置是固定的，格式化輸出即可
python代碼
class Solution(object):
def optimalDivision(self, nums):
"""
:type nums: List[int]
:rtype: str
"""
nums = map(str, nums)
if len(nums) <= 2:
return '/'.join(nums)
return "%s/(%s)" % (str(nums[0]), '/'.join(nums[1:]))
assert Solution().optimalDivision([1000,100,10,2]) == '1000/(100/10/2)'
assert Solution().optimalDivision([2]) == '2'
