Coding (Algo)

Weighted shortest paths: relax non-negative weighted edges in increasing tentative-distance order

Weighted shortest paths: Given a directed graph with non-negative weighted edges, return the shortest distance from source to every node. Use null for unreachable nodes.

Input: A JSON object { "n": number, "edges": [number,number,number][], "source": number }.

Output: A JSON array of numbers or null values with length n.

Constraints:

0 <= n <= 100000
Edge weights are non-negative safe integers
Nodes are numbered from 0 to n-1

Read one JSON value from stdin and print exactly one JSON-serialized answer to stdout with no extra text.

Difficulty: HARD. Variant: 15. Balance correctness, maintainability, and clear review-ready code.

Practice context

This coding (algo) exercise trains prompt interpretation, explicit assumptions, a concrete response, and a concise explanation of the decisions made. It is marked hard difficulty.

The signed-in workspace provides the tools required

What this task practices

This coding (algo) exercise trains the same sequence expected in an interview: understand the prompt, make assumptions explicit, produce a concrete answer, and explain the decisions behind it. The task is marked hard difficulty. The private workspace adds the tools required by this round, such as recording, code execution, diagrams, evidence panels, or structured notes. It also preserves the attempt so later feedback can be compared with previous work. Evaluation is based on task-specific criteria and the candidate seniority selected in the preparation path. Public pages never expose the reference solution, hidden tests, evaluator instructions, or another candidate’s work.