Dijkstra Algorithm

When edges have weights, use Dijkstra.

Example graph ```python graph = { "A": [("B", 1), ("C", 4)], "B": [("C", 2), ("D", 5)], "C": [("D", 1)], "D": [] } ```

Dijkstra with heap ```python import heapq

def dijkstra(g, start): dist = {start: 0} pq = [(0, start)]

while pq: d, u = heapq.heappop(pq) if d > dist[u]: continue for v, w in g[u]: nd = d + w if v not in dist or nd < dist[v]: dist[v] = nd heapq.heappush(pq, (nd, v)) return dist

print(dijkstra(graph, "A")) ```

Graph ```mermaid flowchart LR A --1--> B A --4--> C B --2--> C C --1--> D ```

Remember - use heap for min distance - works only with non-negative weights