Use a recursive traversal that decides whether to parenthesize each child based on operator precedence and associativity. For each node, serialize the left and right subtrees, adding parentheses only when the child's operator has lower precedence than the parent, or when associativity requires it (e.g., right child of '-' or '/').
Pro tip: Mention that you can avoid parentheses for associative operators like '+' and '*' when the child has equal precedence, but must parenthesize the right child for non-associative operators like '-' and '/'. Also, note that parentheses are never needed for leaf nodes.
Assign precedence levels to operators (e.g., +,-: 1; *,/: 2) and specify associativity (left-associative for all four). This determines when parentheses are necessary.
Write a recursive function that takes a node and the parent operator (or context) and returns the serialized string. For each child, decide whether to wrap it in parentheses based on precedence and associativity.
Add parentheses if the child's operator has lower precedence than the parent, or if the child is the right operand and has equal precedence with a non-associative parent (e.g., '-' or '/').
For leaf nodes (variables), return the variable name without parentheses. For operators, combine the serialized left and right children with the operator symbol.
Verify with expressions like a-b-c (should be (a-b)-c without extra parentheses), a-(b-c) (needs parentheses), and mixed precedence like a+b*c.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.