def dijkstra(graph, start):
    distances = {node: float('inf') for node in graph}
    distances[start] = 0
    pq = [(0, start)]

    while pq:
        curr_dist, curr_node = heapq.heappop(pq)

        if curr_dist > distances[curr_node]:
            continue

        for neighbor, weight in graph[curr_node]:
            # Calculate new path cost
            distance = curr_dist + weight
            if distance < distances[neighbor]:
                distances[neighbor] = distance
                heapq.heappush(pq, (distance, neighbor))