Shortest Path Between Cities with Tolls (Dijkstra)

Question

## Problem

You are given a road network as a weighted directed graph where edge weights represent toll costs. Find the **minimum cost path** between a source city and a destination city.

## Example
```
cities = 5
roads = [[0,1,4],[0,2,2],[1,3,3],[2,1,1],[2,3,5],[3,4,2]]
source = 0, destination = 4
Output: 8  -- path: 0→2→1→3→4
```

## Constraints
- 1 ≤ cities ≤ 10^4
- Non-negative edge weights

## Follow-up variants asked at Ola
- Find shortest path with at most `k` stops
- Find shortest path avoiding certain toll booths
- Multiple sources to a single destination (reverse Dijkstra)