Round 1
Questions: The interviewer drew a circular linked list with unidirectional pointers, where each node represents a fueling station. Each node has a REFILL value, indicating the amount of fuel a vehicle can gain when stopping at that particular node. Additionally, each edge in the linked list has an EXHAUST value, representing the fuel consumption required for the vehicle to travel from one node to another.
Return the node from which a full circular trip over all nodes can be completed.
Candidate's Approach
The candidate proposed the following solution:
struct Node { int refill; int exhaust; Node* next; }; Node* CircularTrip(Node* head) { Node* init = head; Node* temp = head; int fuel = 0; do { fuel += (temp->refill) - (temp->exhaust); if (fuel < 0) { init = temp->next; fuel = 0; } temp = temp->next; } while (temp != head); return (fuel >= 0) ? init : nullptr; }
However, the interviewer was not convinced and asked the candidate to further optimize the solution.
Interviewer's Feedback
The interviewer requested further optimization of the proposed solution, indicating that the initial approach may not be the most efficient.