Rearrange Code Scramble | Dataford Interview Questions

The code blocks in The's code editor were scrambled. Each block lists the blocks that must appear before it because they define required functions, classes, or constants. Restore a valid execution order.

Return the lexicographically smallest valid ordering of block IDs. When multiple currently available blocks can be selected, choose the ID that comes first lexicographically. If the dependencies contain a cycle, return an empty list because no executable ordering exists.

Formal Specification

Implement restore_code_order(blocks), where blocks is a list of dictionaries. Each dictionary has:

id: a unique string identifying one code block.
depends_on: a list of IDs that must appear earlier than this block.

Return a list of block IDs containing every input block exactly once, or [] if no valid ordering exists.

Constraints

1 <= len(blocks) <= 10^5
Each block ID is unique and has length at most 50
Every dependency ID appears in blocks
Each block has at most 10^4 dependencies
The total number of dependency references is at most 2 * 10^5

Function Signature

def restore_code_order(blocks):

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