# 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`

``````class Solution {
public:
vector<int> decompressRLElist(vector<int>& nums) {
vector<int> res;
for (int i = 0; i < nums.size(); i += 2) {
for (int j = 0; j < nums[i]; ++j) {
res.push_back(nums[i + 1]);
}
}
return res;
}
};
``````

Github 同步地址:

https://github.com/grandyang/leetcode/issues/1313

String Compression

https://leetcode.com/problems/decompress-run-length-encoded-list/

https://leetcode.com/problems/decompress-run-length-encoded-list/discuss/521777/Java-100-time

https://leetcode.com/problems/decompress-run-length-encoded-list/discuss/477498/C%2B%2B-vector.insert(end-a-b)

LeetCode All in One 题目讲解汇总(持续更新中…)

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