dijkstra_by_dict.py

import heapq


# https://justkode.kr/algorithm/python-dijkstra
def dijkstra(graph: dict, start: int) -> dict:
    distances = {node: float('inf') for node in graph}
    distances[start] = 0
    queue = []
    heapq.heappush(queue, [distances[start], start])

    while queue:
        current_distance, current_destination = heapq.heappop(queue)

        if distances[current_destination] < current_distance:
            continue

        for new_destination, new_distance in graph[current_destination].items():
            distance = current_distance + new_distance
            if distance < distances[new_destination]:
                distances[new_destination] = distance
                heapq.heappush(queue, [distance, new_destination])

    return distances