树遍历-有序位置

Question

I am trying to find the value of the kth node in tree, using recursive in order traversal.

The code below is done with recursion, but my implementation is way too slow.

Can someone please give me a hint how to make it faster? ( reihe and pos are class variables, they both start from 0, and I save the final result in pos ).

Here is what I have done so far, and any help would be really appreciated:

void valueAtPosition(int k) {

            if(this.left!=null){
                left.valueAtPosition(k);
            }
            if(reihe++==k){
                pos=this.elem;

            }

           else if(this.right!=null){
                right.valueAtPosition(k);
            }
        }

Answer 1

To remove the need for reihe (and I'm assuming it's not english since it makes no sense as a variable name to me). I've passed the variable k as a return value. When it reaches 0, I return the current value and stop searching.

int valueAtPosition(int k) {

    if(this.left!=null k >= 0){
        k = left.valueAtPosition(k);
    }

    if(k == 0){
        pos=this.elem;
    }
    k--;

    if(this.right!=null && k > 0){
        k = right.valueAtPosition();
    }

    return k;
}