LeetCode 2640. Find the Score of All Prefixes of an Array

We define the conversion array conver of an array arr as follows:

• conver[i] = arr[i] + max(arr[0..i]) where max(arr[0..i]) is the maximum value of arr[j] over 0 <= j <= i.

We also define the score of an array arr as the sum of the values of the conversion array of arr.

Given a 0-indexed integer array nums of length n, return an array ans of length n where ans[i] is the score of the prefix nums[0..i].

Example 1:

Input: nums = [2,3,7,5,10]

Output: [4,10,24,36,56]

Explanation:

For the prefix [2], the conversion array is [4] 

hence the score is 4 

For the prefix [2, 3], the conversion array is [4, 6] 

hence the score is 10 

For the prefix [2, 3, 7], the conversion array is [4, 6, 14]

hence the score is 24 

For the prefix [2, 3, 7, 5], the conversion array is [4, 6, 14, 12] 

hence the score is 36 

For the prefix [2, 3, 7, 5, 10], the conversion array is [4, 6, 14, 12, 20] 

hence the score is 56

Example 2:

Input: nums = [1,1,2,4,8,16]

Output: [2,4,8,16,32,64]

Explanation: 

For the prefix [1], the conversion array is [2] 

hence the score is 2 

For the prefix [1, 1], the conversion array is [2, 2] 

hence the score is 4 

For the prefix [1, 1, 2], the conversion array is [2, 2, 4] 

hence the score is 8 

For the prefix [1, 1, 2, 4], the conversion array is [2, 2, 4, 8] 

hence the score is 16 

For the prefix [1, 1, 2, 4, 8], the conversion array is [2, 2, 4, 8, 16] 

hence the score is 32 

For the prefix [1, 1, 2, 4, 8, 16], the conversion array is [2, 2, 4, 8, 16, 32] 

hence the score is 64

 先是计算convert数组，就是arr[i]+max((0-i)of arr[])

然后pre_sum；

最后返回即可，

不是难的题目；

可能提交的人少，所以数据看着还可以的。

Constraints:

• 1 <= nums.length <= 105

• 1 <= nums[i] <= 109

Accepted

12,032

Submissions

17,385

Runtime: 3 ms, faster than 100.00% of Java online submissions for Find the Score of All Prefixes of an Array.

Memory Usage: 72.5 MB, less than 100.00% of Java online submissions for Find the Score of All Prefixes of an Array.