Cheapest Flights Within K Stops

Implement solve for Cheapest Flights Within K Stops. Return the required output for the provided arguments.

Examples
Input: [4,[[0,1,100],[1,2,100],[2,0,100],[1,3,600],[2,3,200]],0,3,1]
Output: 700
Hints

Cheapest Flights Within K Stops

Implement `solve` for **Cheapest Flights Within K Stops**. Return the required output for the provided arguments.