Leetcode553. Optimal Division

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.

题目看起来很复杂，以为是要用到dp去计算，发现数字范围是2到1000，所以这道题就是单纯的字符串拼接。

public  String optimalDivision(int[] nums) {        int n = nums.length;        if(n==0) return null;        if(n==1) return Integer.toString(nums[0]);        if(n==2) return Integer.toString(nums[0])+"/"+Integer.toString(nums[1]);        StringBuffer ss =new StringBuffer();        ss.append(nums[0]).append("/").append("(").append(nums[1]).append("/");        for(int i=2;i<n;i++){            ss.append(nums[i]).append("/");        }        ss.deleteCharAt(ss.length()-1).append(")");        return ss.toString();    }