写带类型注解和测试的 Python 算法

只是写法示意，不是完整程序。

# ANS Dijkstra 最短路径纯 Python 优先队列标准实现 (ans-py-algorithms.py)
import heapq
def ans_shortest_path(graph: dict, start: str) -> dict:
    dist = {node: float("inf") for node in graph}
    dist[start] = 0
    pq = [(0, start)]
    while pq:
        d, u = heapq.heappop(pq)
        if d > dist[u]: continue
        for v, w in graph[u].items():
            if d + w < dist[v]: dist[v] = d + w; heapq.heappush(pq, (dist[v], v))
    return dist