LeetCode 1313. Decompress Run-Length Encoded List

We are given a list nums of integers representing a list compressed with run-length encoding.

Consider each adjacent pair of elements [freq, val] = [nums[2*i], nums[2*i+1]] (with i >= 0).  For each such pair, there are freq elements with value val concatenated in a sublist. Concatenate all the sublists from left to right to generate the decompressed list.

Return the decompressed list.

Example 1:

Input: nums = [1,2,3,4]Output: [2,4,4,4]Explanation: The first pair [1,2] means we have freq = 1 and val = 2 so we generate the array [2]. The second pair [3,4] means we have freq = 3 and val = 4 so we generate [4,4,4]. At the end the concatenation [2] + [4,4,4] is [2,4,4,4].

Example 2:

Input: nums = [1,1,2,3]Output: [1,3,3]

Constraints:

• 2 <= nums.length <= 100

• nums.length % 2 == 0

• 1 <= nums[i] <= 100

依次遍历，放到list中，然后将list放到数组中。list有toarray的方法，但是老报错，还是用原始的方法了。

下面是代码：

Runtime: 4 ms, faster than 55.94% of Java online submissions for Decompress Run-Length Encoded List.

Memory Usage: 44.5 MB, less than 5.84% of Java online submissions for Decompress Run-Length Encoded List.