LeetCode1313. Decompression encoder list (Java implementation)

class Solution {
    public int[] decompressRLElist(int[] nums) {
        int len=0;
        for(int i=0;i<nums.length;i+=2){
            len+=nums[i];
        }
        int[] arr=new int[len];
        int index=0;
        for(int i=1;i<nums.length;i+=2){
            for(int j=0;j<nums[i-1];j++){
                arr[index++]=nums[i];
            }
        }
        return arr;
        
    }
}