Serialize Expression Tree Minimizing Parentheses

Given a binary expression syntax tree, serialize it into an infix string using the minimum number of parentheses required to preserve the tree's evaluation semantics. Each node is one of: - A variable leaf, represented by a non-empty identifier such as `a`, `x`, or `foo` - A binary operator node whose operator is one of `+`, `-`, `*`, `/` and whose left and right children are valid expression nodes Use standard arithmetic precedence: 1. `*` and `/` have higher precedence than `+` and `-` 2. Operators are evaluated left to right when precedence is the same Return a string representation of the expression with unnecessary parentheses removed, but do not change the meaning of the original expression tree. Examples: - Tree for `(a + b) * c` should serialize as `(a+b)*c` - Tree for `a + (b * c)` should serialize as `a+b*c` - Tree for `a - (b + c)` should serialize as `a-(b+c)` - Tree for `(a - b) - c` should serialize as `a-b-c` - Tree for `a / (b * c)` should serialize as `a/(b*c)` Implement a function such as: `string serialize(Node root)` where `Node` contains either a variable name or an operator with left and right children.