memory error

def answer(h, q):
    #Setting up Variables to use later on
    size = (2**h)-1
    tree = []
    vals = []
    final = []
    #Populate Values to be inserted into tree
    #Fill Tree with filler
    for i in range(0,size,1):
        vals.append(i+1)
        tree.append(-2)
    #Function used to insert values to tree
    def addVal(i):
        tree[i] = vals.pop(0)
    #PostOrder Insertion
    def postOrder(i):
        if (i*2)+1 > size or (i+1)*2 > size:
            addVal(i)
        else:
            postOrder((i*2)+1)
            postOrder((i+1)*2)
            addVal(i)
    #returns parent node of a given index
    def getParent(i):
        if i == 0 or i > size:
            return -1
        else:
            return (i-1)/2
    #returns value being stored at indexed node
    def getValue(i):
        if i == -1:
            return -1
        else:
            return tree[i]
    #Populate Tree with Values
    postOrder(0)
    #return List composed of the values of the parents of provided list
    for i in range(0, len(q), 1):
        final.append(getValue(getParent(tree.index(q.pop(0)))))
    #return List with Values of Parents
    return final