Invoice State Machine | Dataford Interview Questions

Write a program to simulate a state machine that transitions a Candid Health billing invoice through various stages (Draft, Submitted, Paid, Rejected) while handling invalid state transitions. Implement simulate_invoice(initial_state, requested_states). Valid transitions are Draft to Submitted, Submitted to Paid or Rejected, and Rejected to Submitted. Paid is terminal. Return a dictionary containing the final state and one result per request, including the requested state, resulting state, and whether the transition was valid. Invalid requests leave the invoice state unchanged.

Constraints

initial_state is one of Draft, Submitted, Paid, or Rejected
Each requested state is one of Draft, Submitted, Paid, or Rejected
0 <= len(requested_states) <= 10^4
Invalid transitions must not change the current state
Paid is terminal

Function Signature

def simulate_invoice(initial_state, requested_states):

Your question is Invoice State Machine. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Constraints

initial_state is one of Draft, Submitted, Paid, or Rejected
Each requested state is one of Draft, Submitted, Paid, or Rejected
0 <= len(requested_states) <= 10^4
Invalid transitions must not change the current state
Paid is terminal

Function Signature

def simulate_invoice(initial_state, requested_states):

Your question is Invoice State Machine. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.