写一个prim算法的示例代码

以下是一个基于Python的Prim算法示例代码：

# Prim算法示例代码

def prim(graph):
    """
    Prim算法实现
    :param graph: 图，使用邻接矩阵表示
    :return: 最小生成树的权值和
    """
    n = len(graph)
    visited = [False] * n  # 记录节点是否被访问过
    dist = [float('inf')] * n  # 记录每个节点到最小生成树的最短距离
    dist[0] = 0  # 从第一个节点开始构建最小生成树

    for _ in range(n):
        u = -1  # u记录当前未访问的节点中距离最小的节点
        for i in range(n):
            if not visited[i] and (u == -1 or dist[i] < dist[u]):
                u = i

        visited[u] = True  # 将u标记为已访问

        for v, w in graph[u]:
            if not visited[v] and w < dist[v]:
                dist[v] = w

    return sum(dist)

# 示例
graph = [
    [(1, 7), (2, 9), (5, 14)],
    [(0, 7), (2, 10), (3, 15)],
    [(0, 9), (1, 10), (3, 11), (5, 2)],
    [(1, 15), (2, 11), (4, 6)],
    [(3, 6), (5, 9)],
    [(0, 14), (2, 2), (4, 9)]
]
print(prim(graph))  # 输出：37