EVALUATE EXPRESSION TREE

Problem - All leaf node in the tree are operands, always positive number. All the other nodes represents operator.

-1 represents addition

-2  : subtract

-3 : division

-4 : product

APPROACH : think about base case. If you are on leaf node then return.

    i.e. if tree.value > 0 : return the value .

    next simply get the left tree value and right tree value and apply the operand respectively using recursion.

    

solution evaluation expression tree