Explain Dijkstra's algorithm at a high level (non-negative weights).

Dijkstra

Shortest path from source with non-negative weights—greedy expand closest unvisited node using min-heap.

// Relax edges from u; if dist[v] improves, push heap
// O((V+E) log V) with binary heap

• Cannot handle negative edges—use Bellman-Ford
• Used in maps routing, network OSPF ideas