Perform Insertion

First thing First, we have to loop throughout the linked list to find where the value of node is greater than our target value. Then, we perform addBefore method to its node.

int a = ll1.ElementAtOrDefault(i);
nodeTemp = ll1.Find(a);
ll1.AddBefore(nodeTemp, 4);
break;

Now, we will not give you oru solved solution fully. Solve on your own algorithm.