1313-Decompress-Run-Length-Encoded-List.cpp

class Solution {
public:
    vector<int> decompressRLElist(vector<int>& nums) {
        
        vector<int> ans;
        
        for(int i=0; i<nums.size(); i+=2){
            ans.insert(ans.end(), nums[i], nums[i+1]);
        }
        
        return ans;
    }
};

/*
    for(int i=0; i<nums.size(); i+=2){
        for(int j=0; j<nums[i]; j++){
            ans.push_back(nums[i+1]);
        }
    }
*/

/* 1313. Decompress-Run-Length-Encoded-List.cpp
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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].

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