DecompRunLenghtEnc.go

/*
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
*/

package main

import (
	"log"
)

func main() {
	tests := [][]int{{1, 2, 3, 4}, {1, 1, 2, 3}}

	for _, test := range tests {
		log.Printf("decompressRLElist(%v) = %v\n", test, decompressRLElist(test))
	}
}

func decompressRLElist(nums []int) []int {
	res := []int{}

	i := 0
	for i < len(nums) {
		if (i + 1) < len(nums) {
			for j := 0; j < nums[i]; j++ {
				res = append(res, nums[i+1])
			}
		}

		i += 2
	}

	return res
}