Related Coding / DSA
Determine a Valid Course Completion Order
Given a number of courses and a list of prerequisite pairs, determine a valid order to complete all courses, or report that no valid order exists.
1. Problem Statement
You are given one-way flight routes between cities, each with a cost, plus a source, a destination, and a maximum number of intermediate stops k. Find the cheapest total cost from source to destination using at most k intermediate stops, or -1 if no such route exists.
2. Live Coding Format
Work in the provided coding workspace while explaining your decisions to the live interviewer. Validation may use inline tests, examples, comments, or a verbal walkthrough.
3. Key Focus Areas
- 1Problem clarification and contract
- 2Approach exploration and optimality
- 3Think-aloud communication and pacing
- 4Implementation correctness
- 5Code quality and language fluency
- 6Handwritten tests and dry run
- 7Debugging and self-correction
- 8Complexity analysis
- 9Follow-up performance
4. What Strong Candidates Should Demonstrate
- ✓Clarify stop-versus-edge counting, cost sign, and no-route behavior before coding.
- ✓Explain an exponential DFS baseline and improve to a stop-bounded relaxation approach.
- ✓Think aloud while implementing careful iteration-limited relaxation.
- ✓Validate with explicit expected outputs and a top-to-bottom handwritten dry run.
- ✓Analyze time and space complexity and handle a focused follow-up extension.
Want interactive feedback?
Practice this problem in the live coding workspace while the interviewer probes your clarification, implementation, trade-offs, and validation.
Continue to DashboardCore Concepts
Shortest PathsGraphsDynamic ProgrammingComplexity Analysis
Continue preparing
Build a complete software engineer mock interview plan
Prepare by company
Related Coding / DSA
Fewest Moves to Solve a Sliding Tile Puzzle
Given a small 2-by-3 sliding tile puzzle board with one blank space, find the minimum number of adjacent tile slides needed to reach a specified target arrangement, or report it is unreachable.
Related Coding / DSA
Longest Strictly Increasing Subsequence
Given a sequence of integers, find the length of the longest subsequence (not necessarily contiguous) whose elements are strictly increasing.
Related Coding / DSA
Minimum Coins to Reach an Amount
Given a set of coin denominations and a target amount, find the minimum number of coins (with unlimited supply of each denomination) needed to make exactly that amount, or report it is impossible.