private Node createTree(int pre[],char val[], PreIndex ind){
        if(ind.index >= pre.length){
            return null;
        }
        Node root = Node.newNode(pre[ind.index]);
        
        if(val[ind.index] == 'L'){
            ind.index++;
        }else{
            ind.index++;
            root.left = createTree(pre,val,ind);
            root.right = createTree(pre,val,ind);
        }
        return root;
    }
http://www.geeksforgeeks.org/construct-a-special-tree-from-given-preorder-traversal/
Test cases:
Length of pre and val is not same
val contains values other than N or L
src/com/interview/tree/ConstructTreeFromPreOrderTraversalWith0or2Child.java